Armory Sponsor
Fork in the road on load development - advice needed. (Page 1 of 2)
Posted: 6/27/2026 8:23:26 PM EDT
|
Friends, I need a recommendation on which avenue to pursue on reloading. I have attempted to develop a MK262 clone load for a MK12 clone rifle unsuccessfully. I would like to shoot this rifle to the weapon systems maximum range of 800 yards. My goal is repeatable sub MOA @100 yards and repeatable single digit SD. Notable things on the rifle: Larue MBT trigger with lighter of two springs, WOA 18” SPR 1:7 twist, .223 Wylde chamber, BCM thermal fit upper, OCM MK12 suppressor, KAC free float rail, Bobro mount, Leuplold MK 5 3-18 power. Scope has been installed and torqued per the Bobro specifications, with a little extra torque applied. Each fastener was installed with purple Loctite per their recommendation and I match marked the fasteners and have seen no movement. Upper was assembled by ADCO. Suppressor is getting eight and three-quarter turns from threading engagement to fully seated hand tight. Load was: CCI #41, 23.8-25.4 grains AA 2520, 77 grain TMK, loaded to 2.305”, shot from a magazine that accommodates that length. The once fired R-P case was annealed, sized with a Forster FL die (expander removed), headspace checked with a Dillon case gauge, neck expanded to 0.222” with a Sinclair mandrel, trimmed to 1.750”, chamfer/ deburred, flash hole uniformed, wet tumbled, and dried in the air fryer at 250F. Cases are hand primed and seated with a Forster micrometer seating die. Charges are hand weighed individually. Throughout load development (0.1 grain increment) the groups have been mediocre, maybe 2-3 out of 25 being sub MOA at 100 yards, the best at 0.85 MOA at 100 yards but normally between 1.25-2.5 MOA. 25.4 grains AA 2520 has produced the best consistency, 2775 FPS, ES 15.1 FPS, SD 5.4 FPS measured on a Garmin, but 0.95 MOA best group, average 2.0+ MOA. I love these numbers except for consistency of group size. I have also shot factory BH MK 262 with and without the suppressor, and got similar results of 2.0 MOA across three 5 shot groups at 100 yards, and 1.9 MOA at 200 yards. Frustrated and ready to troubleshoot the rifle, I shot an old accuracy load with 69 grain SMK’s and 25.7 grain WIN 748, and got several 0.600 MOA groups. This load was not annealed, was not expanded with a mandrel die… just a factory Redding full length size die with the expander, charges were thrown on my 550 which is typically plus or minus 0.5 grain, and seated with a Redding seater die. They are approximately 2.260” COAL. This load was developed 10 years ago before I had a chronograph, and got more articulate with case preparation since then. As a result, the standard deviation is 17.9 FPS averaged across six 5 shot groups. I intend to get to the range in approximately two weeks with a goal of getting further down the path of deciding on a final load for this rifle. I will be adding a suppressor heat cover because the haze is negatively impacting my sight picture. Otherwise, I don’t plan on making any changes to the rifle, but may consider experimenting with a new trigger just for the sake of trying something new, and further eliminating human error from the equation. So here are my questions: 1. Have you ever had a rifle that didn’t like a bullet weight? 2. Have you ever had a rifle that didn’t like factory match ammo? 3. Are there any simple, stupid fixes that I might be overlooking on the rifle? In my loading process? 4. Most importantly, which avenue would you pursue with load development? 77 grain TMK, or 69 grain SMK? I’m confident with the tools and knowledge I have now I can probably get the standard deviation on the 69 grain SMK down a little bit more. 5. Based on how you answered number four, what would you do next? Experiment with seating depth, change powders, experiment with charge weights etc. 6. What is your favorite AR trigger for precision shooting? I do not want recommendations on hair-trigger, or bench-rest triggers. Something with at least a few pounds force needed to fire. Are there G$ sales on the 4th of July? 7.Anything I am missing/ overlooking? Thanks for reading this long post and I look forward to seeing your recommendations. |
|
Attached File 69 grain group: 0.825” end to end, 0.601” center to center, 0.575 MOA. Attached File 77 grain group: 1.964” E2E, 1.740 C2C, 1.66 MOA |
|
Geissele High Speed National Match trigger (watch Primary Arms for 4th of July Blem Specials down around $200). Ream your chamber throat from Wylde to 5.56 NATO. Drop Tipped Match Kings for the Match King. The Tipped (in my experience) have never grouped as well and I've seen tips that were off-axis. You won't beat 69 Match Kings at 200, or 300 on a calm day (24.5 of Varget, RE-15, or VV N140). If you're going to stick with 77s try 24.5 of Varget or 23.4 of IMR 8208. Get away from GI primers for CCI 450s or Remington 7 1/2s. You might splurge for BR4s. How do you test for groups? Sandbags fore and aft? NO bipod? This was a function-fire test group (third group fired from this rifle) with a newly-assembled 20-inch match rifle using a Criterion 20-inch barrel, rifle rested on top of an ammo can and sandbag. Sierra 69-grain Match Kings, 24.5 Varget. Attached File |
|
Originally Posted By Sinister: Geissele High Speed National Match trigger )watch Primary Arms for 4th of July Blem Specials down around $200). Ream your chamber throat from Wylde to 5.56 NATO. If you're going to stick with 77s try 23.4 of IMR 8208. Get away from GI primers for CCI 450s or Remington 7 1/2s. You might splurge for BR4s. How do you test for groups? Sandbags for and aft? NO bipod? I have some standard FGMM primers (Not the newer AR primers). I shot the groups on a Harris bipod (front) Caldwell (rear) bag. |
|
You no doubt chose your powder, to try to get to BH's impressive velocities. However, folks that shoot 77gr sierras for groups pretty mucn only use Varget or Reloder 15. These will not yeild the results in velocity you are probably after. A hand tight suppressor will generally get loose after a few rounds and need more tigntening, failing to do this will cause group problems for sure. If it were me, I was dead set set on this powder, I would remove the suppressor for now and put a brake on. The next variable, as mentioned, would be to move to cci-450 primers. Maybe try single feeding them, and rule out bullet setback due to not enough neck tension. |
|
I'm not as meticulous with my reloading technique and I've gotten really good results with 8208XBR powder with LC brass, 77gr SMK bullets and CCI 41 primers. Actually was able to hit a 900 yard target with that load. Another good one for me is AR-Comp powder, 77gr TMK bullets, LC brass and CCI 41 primers. I never had any luck with A2520 powder and 77gr bullets. It was somewhat accurate but no wow factor so I moved on to other powders. I believe the standard load is using Varget but it doesn't meter well. |
|
Originally Posted By WillieTangoFox: You no doubt chose your powder, to try to get to BH's impressive velocities. However, folks that shoot 77gr sierras for groups pretty mucn only use Varget or Reloder 15. These will not yeild the results in velocity you are probably after. A hand tight suppressor will generally get loose after a few rounds and need more tigntening, failing to do this will cause group problems for sure. If it were me, I was dead set set on this powder, I would remove the suppressor for now and put a brake on. The next variable, as mentioned, would be to move to cci-450 primers. Maybe try single feeding them, and rule out bullet setback due to not enough neck tension. I will double check the procedure for tightening the AEM/OCM. By hand tighten I should have said I’m tightening the suppressor firmly into the collar by hand. |
|
That style suppressor shouldnt be a problem. A recent similar story of my own, i just went through load development for a new Howa 1500 in 6.5cm. The berger hybrid 140s and H4350 have always been good for me. Really did not shoot well.... at all. In fact none of the H4350 groups were all that great. A few .75s here and there but i knew the barrel wanted to group better. I have only ever loaded 6.5cm with H4350..... for like 8 years. Switched to Reloder 17, which i basically have zero expirience with. Berger 140s and Hornday 147s printing 10 shot .4" at 100y. Better yet, R17 gets better velocity at lower pressure. You gotta go with the flow. |
|
OP: Just a few suggestions: -As others have said: Dont shoot off a bipod. Use a bag up front. -I've gotten really good results from the 77TMK's at regular mag length- +- 2.25" and around 2750 muzzle. ( See the validation group here: https://www.ar15.com/forums/ar-15/-ARCHIVED-THREAD-200yd-Groups-Velocities-of-Winchester-62OT-mk318-64-GD-and-others-/16-744061/ ) A true 10 shot sub MOA 77TMK group. Me personally would try that first. Then as other dude suggests, use a SMK instead. You want a MK262 clone- it uses that, not a TMK. |
|
The fact your gun doesn't like factory mk 262 does not encourage me to think your going to do much better but i wish you luck. You are going to have to turn the big nobs and pray it's not the barrel Powder & bullet----- if i read correct you are using the tmk's?? some people say the tipped version picky to my limited knowledge mk 262 only used regular 77 mk's I know tac will get u to your desired velocity but in hot climates it will get spicy / over pressure imo. IF you can ever locate power pro 2000 mr that stuff produces more velocity without pressure signs than any powder i've seen. |
|
I have had tremendous success with N540. Velocity and precision with 69gr bullets from 1:7 Colt barrel. In fact, only powder I have ever used that easily matched published velocity data. You have the ability to experiment! You have proven it with your patience. Maybe 75 gr or 69 gr bullets will work. Maybe they will not! I have been watching Henry and Josh on 9 hole reviews. Henry is very adamant that group size is sometimes over rated when many of his rifles are still capable of satisfactory results on the range. Be realistic and accept your results and spend your time and resources shooting and training rather than experimenting??? |
|
I will likely buy the G$ HSNM and give it a try. I like the fact that it has a few different springs with it. Does anyone have a front and rear bag recommendation that I can buy from Brownells? I may just get the front bag that pairs with the rear bag I already have… photo below. Attached File Thanks! |
|
If you don't think it will shoot well with the load you have, you can just pick a standard load that a service rifle shooter would use. Say for instance 24gr of N140. If you want more precision, drop it down to 23gr and look at mean radius instead of group size. If the TMKs don't work, try the SMKs or the 73 ELDm or 77 Bergers. I'd also encourage you to stop trying to give the full on Eric Cortina treatment to an AR. Trying to develop a load with .1 grain charges in an AR is not a really useful endeavor in my experience. |
|
OP, I've had 2 of the the same barrels you are using. Both wouldn't put up a good group at all. The upper was sent back to the manufacture. They disassembled the upper and put to back together and shot it. They agreed it didn't shot well so they replaced the barrel. The second barrel shot poorly as well. Life got in the way and I never addressed the second barrel issues with them. I have one of their 20" national match complete uppers that shoots lights out. Easily the best shooting rifle in my safe. OP, replace the barrel with something else. Might be the best $300 you spent. |
|
Lots of good advice here... Ive never found the TMK to be as accurate as the SMK from an AR. I think the tip struggles with the violent action of the AR and the feed ramps can potentially mess up the tips. Could just be me. AA2520 is a good powder, but not the powder Id use for this. Ball powder works sometimes, but then the rest of the time youre chasing your tail. I suggest IMR 8208 for powder. Its temp stable, short cut kernel for high load density, and meters well in the powder drop. Varget and N140 are also good, but due to them being kinda chunky, you may not be able to get enough in the case to hit 2800 fps. Stop using arsenal primers. CCI 41s are great for heavy charges of ball powder where you are using a temp sensitive ball powder, but they are really not suited to accuracy. Try a standard CCI 400 as a test. Yes, they will flatten, but Ive never had one pierce with 8208. If not happy try a CCI 450 or BR2. My load is very similar to alot of other peoples. 23.4gr 8208 XBR LC brass CCI 400 77 SMK 2.255" COAL 2820 FPS from a 20" Wylde Criterion barrel and shoots happily right around 1/2" if I do my job. I have tested mags that allow 2.31 COAL, but honestly it just muddied the water, and made me have to keep specific mags on hand for that specific loading. If you dont care about that? It will allow you to do some depth testing without running into running heavy compressed loads. As far as bags? If youre happy with your bipod, then use it. For a rear bag, I suggest just making one. Go to Walmart, buy some pantyhose, and a couple pounds of pinto beans, and make one. You can make it as big or small as you want, or as loose or tight as you prefer. Word on panty hose? Dont steal the wifes, and when you buy it, buy decent stuff so it doesnt snag and rip on everything. |
|
Thanks for the reply so far. After the Fourth of July, I’m going to order some different primers and powders to experiment with, as my local shop doesn’t have a lot of of the things you’ve collectively suggested. In the meantime, I’ll experiment with some powders and primer combos that I have on hand and report back. I will also try out a front bag… they are cheap enough to try. I will also make a squeeze bag for the back. Next range session I will try the HSNM trigger too. |
|
Originally Posted By carcrazysammy: OP, I've had 2 of the the same barrels you are using. Both wouldn't put up a good group at all. The upper was sent back to the manufacture. They disassembled the upper and put to back together and shot it. They agreed it didn't shot well so they replaced the barrel. The second barrel shot poorly as well. Life got in the way and I never addressed the second barrel issues with them. I have one of their 20" national match complete uppers that shoots lights out. Easily the best shooting rifle in my safe. OP, replace the barrel with something else. Might be the best $300 you spent. Well that is unfortunate. I chose this barrel based on how a friends barrel shot. He shot about 0.4-0.5 MOA with a MK 262 clone load, but to be fair his rifle was setup more like a bench rest rifle. I would not consider my barrel not shooting well, my mass production accuracy load tested in a different rifle shot approximately 0.575 MOA at 100 yards, which is a good group with me shooting. I would really like to take advantage of a bullet with better BC and terminal performance hence the 77 grain TMK starting point.. |
|
Personally, I stay away from tipped bullets. Get the 77 SMK or 69 SMK, instead, at least until you work this out. If you want to really know, get a box of 52 SMK. If those won't shoot, it's you or the rifle (most likely you). Get match quality primers, just to be sure. Federal GMM and a few others are available. Get some cases that are weight-matched. <-- just to be sure, until you get it worked out. My experience with factory ammo has been disappointing. My reloads have always been able to outperform factory ammo: many times by a lot. My AR's do not like being shot from a bipod. Literally, I do better or just as good with a sling. So, get a front bag like this and give it a try. Heck, even a sand bag (free) would do the job.  |
|
Originally Posted By Trollslayer: Personally, I stay away from tipped bullets. Get the 77 SMK or 69 SMK, instead, at least until you work this out. If you want to really know, get a box of 52 SMK. If those won't shoot, it's you or the rifle (most likely you). Get match quality primers, just to be sure. Federal GMM and a few others are available. Get some cases that are weight-matched. <-- just to be sure, until you get it worked out. My experience with factory ammo has been disappointing. My reloads have always been able to outperform factory ammo: many times by a lot. My AR's do not like being shot from a bipod. Literally, I do better or just as good with a sling. So, get a front bag like this and give it a try. Heck, even a sand bag (free) would do the job. https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fimage.sportsmansguide.com%2Fadimgs%2Fl%2F6%2F644465_ts.jpg&f=1&nofb=1&ipt=5583f2105f527cbec3af58ff62872d98059268df3aa1e0a13c199621e039c58a I was not sure which front bag to get, but I will grab that one. |
|
Originally Posted By Romano316: Well that is unfortunate. I chose this barrel based on how a friends barrel shot. He shot about 0.4-0.5 MOA with a MK 262 clone load, but to be fair his rifle was setup more like a bench rest rifle. I would not consider my barrel not shooting well, my mass production accuracy load tested in a different rifle shot approximately 0.575 MOA at 100 yards, which is a good group with me shooting. I would really like to take advantage of a bullet with better BC and terminal performance hence the 77 grain TMK starting point.. I'd contact White Oak and see what they have to say. Id bet they will take your upper and test it. They will probably re-barrel it unless they find some sort of other issue. The turnaround was 30 days or so. The 77g SMK is a much easier bullet to find good loads for. The 77g TMK gold standard load is 23.4g of 8208. It shoots well in all my rifles. This if I recall was shot with a Geisselle 16" upper, 100 yards 10 shots with an ACOG if I recall correctly. 
|
|
Originally Posted By Trollslayer: Personally, I stay away from tipped bullets. Get the 77 SMK or 69 SMK, instead, at least until you work this out. If you want to really know, get a box of 52 SMK. If those won't shoot, it's you or the rifle (most likely you). Get match quality primers, just to be sure. Federal GMM and a few others are available. Get some cases that are weight-matched. <-- just to be sure, until you get it worked out. My experience with factory ammo has been disappointing. My reloads have always been able to outperform factory ammo: many times by a lot. My AR's do not like being shot from a bipod. Literally, I do better or just as good with a sling. So, get a front bag like this and give it a try. Heck, even a sand bag (free) would do the job. The OP wants to shoot out to 800yds. Certainly try the 77 SMK's but I wouldn't waste time with the 69's and 52's if that is the goal. The same thing applies....... there are more than a few good 77 SMK loads......... try one and if accuracy isn't there, as you say it's either the barrel or the shooter. But why wonder down the 52/69 load road only to then switch to a 77 load ? |
|
Originally Posted By carcrazysammy: I'd contact White Oak and see what they have to say. Id bet they will take your upper and test it. They will probably re-barrel it unless they find some sort of other issue. The turnaround was 30 days or so. The 77g SMK is a much easier bullet to find good loads for. The 77g TMK gold standard load is 23.4g of 8208. It shoots well in all my rifles. This if I recall was shot with a Geisselle 16" upper, 100 yards 10 shots with an ACOG if I recall correctly. https://www.ar15.com/media/mediaFiles/109231/20240406_204114-3180690.jpg @carcrazysammy I see you're at 2.25 with the TMK's. That is where I found accuracy with it. What velocities were you getting? Around 2750 ish? |
|
Originally Posted By TGH456E: The OP wants to shoot out to 800yds. Certainly try the 77 SMK's but I wouldn't waste time with the 69's and 52's if that is the goal. The same thing applies....... there are more than a few good 77 SMK loads......... try one and if accuracy isn't there, as you say it's either the barrel or the shooter. But why wonder down the 52/69 load road only to then switch to a 77 load ? Why do it? Well, my whole post is targeted at sorting out whethere this is a rifle issue or a shooter issue or a bullet issue (the TMK). Any of those three bullets will be unimpeachable for accuracy capability, especially so the 52 SMK. Once the issue is found and remedied, only then the OP can think about 800 yards. |
|
Originally Posted By TGH456E: @carcrazysammy I see you're at 2.25 with the TMK's. That is where I found accuracy with it. What velocities were you getting? Around 2750 ish? Unfortunately I'm well short of that. It was low 2600 fps with a 20" barrel. I don't recall exactly and didn't document it. |
|
Originally Posted By carcrazysammy: Unfortunately I'm well short of that. It was low 2600 fps with a 20" barrel. I don't recall exactly and didn't document it. 2600 to 2650 fps is a very useful window for an accuracy load using 75/77 grain bullets and a 20" barrel. Many people mare obsessed with duplicating M262 and other "military spec" loads, missing a huge window for the best accuracy in the process. I will happily trade 100 fps to get tighter groups. M262 is HOT as issued, maybe too hot for the best accuracy. A previous posted suggested reaming .223 Wylde chamber throats to NATO spec. I don't see how that would help at all. |
|
Originally Posted By borderpatrol: M262 is HOT as issued, maybe too hot for the best accuracy. A previous posted suggested reaming .223 Wylde chamber throats to NATO spec. I don't see how that would help at all. Absolutely, most loads do not shoot at the top end. The Sierra accuracy loads recommended, are almost always 100fps slower than the hunting loads. Also, the Wylde chamber freebore is actually longer than the NATO chamber, but the diameter is wider by a little more than .002. I agree that reaming isn't going to improve precision with the 77s, when the 69s are reported to shoot just fine. |
|
My service rifle 200/300 yard load is 77 Lapua SCENAR, LC Brass (sized with 0.244 bushing and then mandrel), CCI450 2.255" and a light LFC (yes, I crimp, the shoot better with LFC), and 23.1 gr 8208. Out of a 20" 1/8 Shilen Match barrel Wylde chamber - Malonited, I get 2775 FPS and my records claim 0.6 MOA in testing. I'm not going to claim I can deliver that all day every day, but it does shoot very well for me. |
|
Hornady also makes a bullet that works at long distances. I was scoring for a guy using an ELD bullet in his AR. This was a 1,000 yard match. He was still supersonic with well over 1400 fps at 1,000 yards (my 6 mm was only 1600 fps at that distance). He outscored me by a bunch (which is not surprising), proving it's the archer not the arrow. Also proving you don't need to be the fastest to do well. I also remember a guy holding up a TMK with its tip all bent out of place. |
|
Shot with the Caldwell tack driver and G$ HSNM trigger and light spring set tonight, shot the rest of my 77 TMK’s and 69 SMK’s I had loaded to confirm it was not me messing up. I also experimented with some powder and primers I had on hand. I will post a summary tonight. Similar findings as before, but definitely some interesting things to note. I am ordering 77 grain SMK/ Bergers, REM 7.5/ BR-4’s, and 8208/ Varget tonight. |
|
Originally Posted By Nobody69s: I'm not as meticulous with my reloading technique and I've gotten really good results with 8208XBR powder with LC brass, 77gr SMK bullets and CCI 41 primers. Actually was able to hit a 900 yard target with that load. Another good one for me is AR-Comp powder, 77gr TMK bullets, LC brass and CCI 41 primers. I never had any luck with A2520 powder and 77gr bullets. It was somewhat accurate but no wow factor so I moved on to other powders. I believe the standard load is using Varget but it doesn't meter well. @Nobody69s can you post your 77 grain smk/ 8208/ CCI 41 load? ETA- another poster put 23.1 grains. Is this your experience? |
|
Originally Posted By Romano316: @Nobody69s can you post your 77 grain smk/ 8208/ CCI 41 load? ETA- another poster put 23.1 grains. Is this your experience? Make sure you work up to it in your barrel. Let me know if you have any other questions. |
|
Originally Posted By Nobody69s: I'm at 23.5 grain of 8208 but it's a pretty hot load. Only using LC brass with an OAL of 2.246" with a light crimp with a Lee factory crimp die. Make sure you work up to it in your barrel. Let me know if you have any other questions. Thank you. |
|
Originally Posted By Romano316: I would like to shoot this rifle to the weapon systems maximum range of 800 yards. WOA 18” SPR 1:7 twist, .223 Wylde chamber, BCM thermal fit upper, Load was: CCI #41, 23.8-25.4 grains AA 2520, 77 grain TMK, loaded to 2.305”, shot from a magazine that accommodates that length. My NM Service rifle is pretty similar: WOA 20" Wylde chamber 1/7, BCM upper, 4.5X Vortex PST Load: SMK 77 or Nosler 77, 24.5gr AA2520, Win SRP, LC brass, loaded on progressive, usually just less than 1 MOA, but never more than that. Don't know velocity or SD's-never measured it. ShotMarker target system does record velocity and SD's at 500yd target: Velocity 1807 fps, SD of 27 500 or 600yd targets depending which KD range assigned. Prone, single fired, sling/coat/glove, no sandbags or other support. Have to factor my wobbly elbow making a 2 MOA group at distance. I'm surprised you are having issues keeping rounds under 2 MOA-with most ammo and handloads. I have heard TMK can be more finicky, but have no experience using them since it's always Nosler or Sierra MK that I use. It may be worth contacting WOA and see what they say. You might just have gotten a bad barrel. Typical target:  
|
|
I repeated two of my loads that gave me the “best” consistency and/ or accuracy in previous testing while the other bullets/ powder/ primers show up. Each round is 2.300” and shot through a magazine that accommodates them. Two 5 shot groups 24.9 grain AA2520, CCI 41, and 77 grain TMK. -1.680/ 1.700 MOA. -11.8/ 9.4 SD. -31.2/ 26.0 ES. Same load with FGMM primers. NOT FGMM AR Primers. -1.060 MOA. -23.6 SD. -64.1 ES. -11 FPS average faster than CCI #41. Two 5 shot groups 25.4 grain AA2520, CCI 41, and 77 grain TMK. -1.600/ 0.968 MOA. -4.4/ 4.8 SD. -11.8/ 14.1 ES. Same load with FGMM primers. NOT FGMM AR Primers. -Unknown MOA shot wrong target but estimate about 1 MOA based on the 4 shot group  -22.4 SD. -64.3 ES. -30 FPS average faster than CCI #41. Observations on this round - -FGMM primer improved group size but turned my SD/ES to crap. -FGMM produced higher velocities. -I want he 25.4 grain AA2520 to shoot well, it pulls a nice group from time to time. Next round same bullet/ CCI #41 primer with WIN 748. Best accuracy group poor other numbers: 5 shot group 24.7 grain WIN 748, CCI 41, and 77 grain TMK. -0.900 MOA. -22.4 SD. -84.3 ES. Observations on this round - -The FGMM groups and this group show improved accuracy when isolating the primer or powder, so I cannot say conclusively which contributes to poor accuracy other than AA2520 and CCI #41 is a losing combo in my rifle. I did four 5 shot groups with 69 grain SMK’s, all were under 0.9 MOA, this is the best result: 5 shot group 25.8 grain WIN 748, CCI 41, and 69 grain SMK. -0.750 MOA. -4.6 SD. -12.1 ES. -2890 AVG FPS. ETA: if I could replicate this accuracy, SD, and ES with a 77 grain load I would be very happy. I did not shoot much better with the tack driver front rest vs the bipod, or from the Larue MBT to the HSNM. That could be a good or bad thing. Thanks for reading and the help so far. Question for the pros: -Why do you think FGMM primers made my ES/ SD go to crap? |
|
Maybe they’re not hot enough for the ball powders. Summertime isn’t usually the problem, it’s the cold weather. When you switch to a stick powder that initiates a burn more readily you likely will see the gold medal match primers work just fine there. Don’t get too hung up on the chronograph just yet. Like borescopes looking at “rough” barrels they can play mind tricks. |
|
Are these accuracy results for 100 yards? Have you shot at 600 yards or more (800 to 1,000 yards)? A Word of Caution - When using 5 shots, small differences in ES, SD, group size may not be real, may not be statistically significant. For example, your sub-MOA group size difference can change if 20 shot groups are used and, of course, both of the numbers being compared will likely change. Ditto for ES and SD. It seems you have two loads you like. Load 20-25 of each and shoot them. See what you get. The results may be the same or better or worse than what you have currently but the results will be more indicative of what to expect in the future, over the long haul. My Perspective - Group size (accuracy) is where it's at. No matter what the chronograph says about velocity, ES or SD, it is the holes in the target that matter. This is not meant to be snarky or raspy. It is a way to keep you focussed on what matters. Unless you are shooting truly long range (>600 yards), small difference in chrono stats mean nothing. Even at long range, they are only an early implication there may be a difference. At long range you will be challenged by your bullet's stability, mirage and the wind. Small differences in chrono stats will be swamped out by those effects. |
|
Originally Posted By Trollslayer: Are these accuracy results for 100 yards? Have you shot at 600 yards or more (800 to 1,000 yards)? A Word of Caution - When using 5 shots, small differences in ES, SD, group size may not be real, may not be statistically significant. For example, your sub-MOA group size difference can change if 20 shot groups are used and, of course, both of the numbers being compared will likely change. Ditto for ES and SD. It seems you have two loads you like. Load 20-25 of each and shoot them. See what you get. The results may be the same or better or worse than what you have currently but the results will be more indicative of what to expect in the future, over the long haul. My Perspective - Group size (accuracy) is where it's at. No matter what the chronograph says about velocity, ES or SD, it is the holes in the target that matter. This is not meant to be snarky or raspy. It is a way to keep you focussed on what matters. Unless you are shooting truly long range (>600 yards), small difference in chrono stats mean nothing. Even at long range, they are only an early implication there may be a difference. At long range you will be challenged by your bullet's stability, mirage and the wind. Small differences in chrono stats will be swamped out by those effects. Out to 600 yards so far. |
|
Originally Posted By Romano316: -FGMM primer improved group size but turned my SD/ES to crap. Question for the pros: -Why do you think FGMM primers made my ES/ SD go to crap? I'm no pro, but shoot enough at 600yds to give an opinion. If the primer makes the groups shrink and the accuracy is good at 600yds it doesn't matter. |
|
VARGET gave me slightly smaller groups than did TAC - 1/2 MOA vs 3/4 MOA (tested at 200 yards). Both group sizes are quite good, so, I use both. I use 23.5 gr of TAC for the 75 gr Hornady HPBT-M seated to 2.240" OAL short range loads. I use 24.0 gr of VARGET for my 80 SMK seated 0.020" off the lands 600 yard loads. I use Winchester commercial brass and Winchester SR primers (blue box). Interestingly, the point of impact was not significantly affected by wide variations on powder charge. Also, there were no signs of high pressure above or below these charge weights. I mention this because of the implications for accuracy and safety. I offer these as points of reference for you. I wonder how they compare to what others are using. Remember, you have to work up your own loading in YOUR rifle(s). |
|
Originally Posted By Romano316: @Metonymy I have #4 of TAC here I’ll try some. What powder weight worked best for you? What primers did you use? Thanks! 24.6gr of TAC. (It's spicy!) Remington 7 1/2 primers 77gr SMK Lake City brass 1.750" trim length 2.258 OAL .002 neck tension |
|
Shot 16 groups today, breakdown as follows: For all loads, 77 gr. SMK/ RP Case/ CCI #41/ 2.300” COAL. AA 2520: 25.2-25.4-25.6-25.8 grains. WIN 748: 24.5-24.7-24.9-25.1 grains. Varget: 23.8-24.0-24.2-24.4 grains. 8208: 23.0-23.2-23.4-23.6 grains. The two loads that showed the most promise were 23.2 grains of 8208 XBR and 24.4 grains of Varget. Attached File Attached File I am going to ‘experiment’ +0.1 and -0.1 grains from these next session. I still have FGMM and CCI BR primers to experiment with. Next session plan: 23.1/ 23.2/ 23.3 8208 and 24.3/ 24.4/ 24.5 Varget with the CCI #41, CCI BR and FGMM primers 90 total rounds. That should narrow me down to one powder weight and primer for 8208 and one powder weight and primer for Varget. Thoughts? What would you do next if you were me? I still have Berger 77 grain OTM to experiment with but don’t HAVE to. |
| Try RP 7.5 primers, Its all I use for small rifle primers any more...Been very happy with how good RP primers work in all my rifle calibers(I use 7.5's/9.5's and 9.5M's).....After that play with OAL as much as you can within mag length, that can help close up groups as well....I doubt you will see much if any improvement bumping charge weight up/down 0.1 grains... |
|
Friends, wanted to provide a final update, but first, thanks to everyone who took the time to help refine the hand-load, my marksmanship skills, or both on my MK12 build, including those who may have gotten frustrated throughout. This is the first build I did that has a reasonably good barrel and higher magnification so it has been a learning experience for me. I did not expect my initial testing to be so bad across the board hence why I started this thread. The three main things that I think made my initial loading and testing bad: 1.Factory new R-P brass sucks. See below photo. 2.Loading past mag length hurt my accuracy in the testing I did with my rifle. 3.I had a little adjustable stock play and upper to lower receiver play that impacted getting a stable firing position, cheek weld, and sight picture. This did not change the mechanical accuracy of the gun, more my ability to shoot it accurately. I was recommended about $1,000 in rifle parts, shooting gear, and loading supplies… and I bought most of it. I spent some time off from work loading and shooting, here is what I found. Johnnys MK262 load (Johnnys Reloading Bench on YouTube) works similarly well in my rifle. We have the same barrel BTW. Attached File LC Case, CCI #41 Primer, 25.2 grains AA 2520, 77 grain SMK (mine is non-cannelure, no crimp, his was cannelure and 0.002” crimped… that was the only difference). Same load on the group to the right, except that is factory new R-P brass. Not a great statement to their out of the box quality. I don’t believe in flyers, but it is possible a better marksman would have kept that shot on the left a little more to the right... there could be more potential there. Factory MK 262 had a SD of 13.8 FPS for 5 shots in my rifle. 8208 and Varget did not meet the accuracy and/ or velocity I was looking for in the testing I did with my rifle. CCI Bench Rest primers did not produce good groups and had the highest average SD between FGMM and CCI#41 in the testing I did with my rifle. If someone is interested, here are the two loads that show accuracy node promise that I will explore +/- 0.1 grain with 10-20 shot groups/ 10-20 shot chronograph averages, and ultimately some seating depth tweaks: Note these are TMK not SMK. 24.2 grains AA 2520, FGMM Primer, 77 grain TMK: Attached File 25.1 grains AA 2520, CCI #41 Primer, 77 grain TMK: Attached File |
Global Warming Hoax Skeptic before it was cool
Joined:
Jun 2007
Posts:
72948
EE: 100% (1)
WA, USA
Fork in the road on load development - advice needed. (Page 1 of 2)
Armory Sponsor