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Posted: 12/10/2013 8:19:34 AM EDT
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Are most chambers on AR15 long throats? I have a DPMS Oracle 5.56/223 16" 1-9 twist and tried to use Hornady OAL tool and none of the bullets I used would fit in case neck when I found touch. I tried 55gr Zmax and Horn 68 BTHP bullets. Seems this chamber is really long throat. I am trying to work up a single load target load(magazine length not an issue here)
Anyone experience this or is this common on ARs? |
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5.56 NATO has a longer throat that 223, so yes that sounds about right.
Most AR's should be 5.56 chambers. Mag length will determine OAL in an AR, with the exception that some high power shooters load long for certain long range stages - these rounds have to be individually loaded as they won't fit in the mag. |
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Only the heaviest bullets in .224 can be loaded to touch the lands on a standard rifle, and these are so long as they have to be single loaded. 75-80 gr bullets. With all other bullets, load to slightly less than mag length. Your loads will still shoot well. Easy to get less than moa groups with quality bullets, tuned load, and standard reloading practices with some attention to detail. |
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thanks. I usually single load anyway when I shoot targets. So sounds like this is normal Thanks I am going try to work up some load this weekend with the 55zmax until I can get my 69 SMK ordered Sir, FWIW single loading is required in all slow fire stages in high power competition. Most service rifle high power competitors that have the option choose 80gr Sierra Match King bullets or the equivalent weight VLDs by Berger or JLK. Especially with the VLDs seating the bullets into the lands usually results in better groups. With JLKs I seat bullets +.030" into the lands of my "long throat" chamber. HTH, 7zero1. |
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I have yet to see an off the rack AR that does not have a long throat. But it's not smart to assume all of them do, or for other types of rifles (bolt guns, Contenders, etc.) that shoot this or any other cartridge. Sir perhaps I should have mentioned that the barrels of my AR15s are Kreiger match grade stainless steel and were chambered by my gunsmith using a reamer of his design. So yes the chambers have a "long throat" but not generally such as one would find in an "off the rack AR". Yes, I agree one should know the throat orientation of his rifles and determine seating depth based on that knowledge. 7zero1 out. |
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I understand HP single load and use heavier barrels.
I just did it when I first started shooting my AR because I was unsure how feeding from magazine and bolt slamming home would affect the round and accuracy. For my plinking loads for my wife we load in magazine and just shoot them |
| I was curious as to distance to lands in AR's so I tested Hornady 55 FMJ's and the distance to the lands in two popular brands of AR's. One rifle to touch the lands with Horn. 55 FMJ's the overall length was 2.370" and the other rifle 2.390" and the bullet was just about falling out of the case neck. Now in a bolt action rifle the overall length to touch the lands was 2.246" with the same 55 FMJ bullet. Also tested Sierra's 77 gr. MK BTHP bullet in a National Match rifle to touch the lands the overall length was 2.316". Only bullets that you can get near the lands is some 75 gr. Match and 80 and 90 grain Match bullets. With 80 gr. Sierra MK BTHP bullets the overall length in a National Match AR the overall length was 2.472". and my loads with the 80 gr. Sierra my overall length of loaded rounds was 2.459" and I'm trying for .015" jump to the lands. Just shows that it doesn't make much difference when loading rounds to fit in the magazine. Seat bullets to recommended lengths and total reliability and don't try pushing short bullets out to maximum mag length at 2.260". |
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Unless you have a Wylde chambered barrel I wouldn't bother trying to find the lands and even then it is prolly not going to give you much gain in an AR. I personally only load to fit in my mags for Semi-auto. YMMV Sir, so that means you don't care about the ballistic advantages offered by heavier, high BC bullets at mid or long range? 7zero1 out. |
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Are most chambers on AR15 long throats? I have a DPMS Oracle 5.56/223 16" 1-9 twist and tried to use Hornady OAL tool and none of the bullets I used would fit in case neck when I found touch. I tried 55gr Zmax and Horn 68 BTHP bullets. Seems this chamber is really long throat. I am trying to work up a single load target load(magazine length not an issue here) Anyone experience this or is this common on ARs? Snugging up to the start of rifling in standard AR chambers may not work well for the 55 Zmax. Those flat base bullets are about .02 shorter than the FMJBTs of same weight. The freebore jump to rifling is going to be alot more than the vaunted .020", and still have sufficient mechanical connection to the case neck. The 68 BTHP bullets may be of sufficient length to allow setting them close to the lands and still have a sound mechanical connection to the neck of the case. |
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Sir, so that means you don't care about the ballistic advantages offered by heavier, high BC bullets at mid or long range? 7zero1 out. Quoted:
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Unless you have a Wylde chambered barrel I wouldn't bother trying to find the lands and even then it is prolly not going to give you much gain in an AR. I personally only load to fit in my mags for Semi-auto. YMMV Sir, so that means you don't care about the ballistic advantages offered by heavier, high BC bullets at mid or long range? 7zero1 out. Not sure of your point...OP is not asking about heavier bullets... I load the 75's and 77's to fit in my mags and go. I still take advantage of the heavier bullets with higher BC's. OP is loading 55g V/Z-max bullets in which he will never find the lands and have enough bullet retained in case to be safe. In my opinion, adjusting seating depth other than to fit the mag in a semi-auto is a waste of time. If loading for a bolt gun I take full advantage of tweaking seating depth. |
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Not sure of your point...OP is not asking about heavier bullets... I load the 75's and 77's to fit in my mags and go. I still take advantage of the heavier bullets with higher BC's. OP is loading 55g V/Z-max bullets in which he will never find the lands and have enough bullet retained in case to be safe. In my opinion, adjusting seating depth other than to fit the mag in a semi-auto is a waste of time. If loading for a bolt gun I take full advantage of tweaking seating depth. Quoted:
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Unless you have a Wylde chambered barrel I wouldn't bother trying to find the lands and even then it is prolly not going to give you much gain in an AR. I personally only load to fit in my mags for Semi-auto. YMMV Sir, so that means you don't care about the ballistic advantages offered by heavier, high BC bullets at mid or long range? 7zero1 out. Not sure of your point...OP is not asking about heavier bullets... I load the 75's and 77's to fit in my mags and go. I still take advantage of the heavier bullets with higher BC's. OP is loading 55g V/Z-max bullets in which he will never find the lands and have enough bullet retained in case to be safe. In my opinion, adjusting seating depth other than to fit the mag in a semi-auto is a waste of time. If loading for a bolt gun I take full advantage of tweaking seating depth. Sir, sorry if my post appears out of context as pertaining to the posts regarding the use of lighter bullets. I was referring to my and other posts that mentioned using heavier and higher BC bullets for the ballistic advantages at longer ranges. There are many service rifle high power competitors that use the heavier high BC bullets single loaded in an AR15 for the longer distance stages of a match and adjusting seating depth to facilitate such use is as important with an AR15 as it is with a bolt action rifle. To shoot at the highest levels in service rifle competition using the heavier, higher BC bullets is a nobrainer IMHO. I've used the 75s and 77s loaded to mag length for 600yd competition and found them significantly inferior to the higher BC bullets. I use them at all distances short of 600yd. Sorry for my failure to be more explicit. To each his own. 7zero1 out. |
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Sir, sorry if my post appears out of context as pertaining to the posts regarding the use of lighter bullets. I was referring to my and other posts that mentioned using heavier and higher BC bullets for the ballistic advantages at longer ranges. There are many service rifle high power competitors that use the heavier high BC bullets single loaded in an AR15 for the longer distance stages of a match and adjusting seating depth to facilitate such use is as important with an AR15 as it is with a bolt action rifle. To shoot at the highest levels in service rifle competition using the heavier, higher BC bullets is a nobrainer IMHO. I've used the 75s and 77s loaded to mag length for 600yd competition and found them significantly inferior to the higher BC bullets. I use them at all distances short of 600yd. Sorry for my failure to be more explicit. To each his own. 7zero1 out. Quoted:
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Unless you have a Wylde chambered barrel I wouldn't bother trying to find the lands and even then it is prolly not going to give you much gain in an AR. I personally only load to fit in my mags for Semi-auto. YMMV Sir, so that means you don't care about the ballistic advantages offered by heavier, high BC bullets at mid or long range? 7zero1 out. Not sure of your point...OP is not asking about heavier bullets... I load the 75's and 77's to fit in my mags and go. I still take advantage of the heavier bullets with higher BC's. OP is loading 55g V/Z-max bullets in which he will never find the lands and have enough bullet retained in case to be safe. In my opinion, adjusting seating depth other than to fit the mag in a semi-auto is a waste of time. If loading for a bolt gun I take full advantage of tweaking seating depth. Sir, sorry if my post appears out of context as pertaining to the posts regarding the use of lighter bullets. I was referring to my and other posts that mentioned using heavier and higher BC bullets for the ballistic advantages at longer ranges. There are many service rifle high power competitors that use the heavier high BC bullets single loaded in an AR15 for the longer distance stages of a match and adjusting seating depth to facilitate such use is as important with an AR15 as it is with a bolt action rifle. To shoot at the highest levels in service rifle competition using the heavier, higher BC bullets is a nobrainer IMHO. I've used the 75s and 77s loaded to mag length for 600yd competition and found them significantly inferior to the higher BC bullets. I use them at all distances short of 600yd. Sorry for my failure to be more explicit. To each his own. 7zero1 out. No worries. I can understand their use and practice if single loading for competition. In that case, single loading rounds for 600y slow fire, I would be adjusting for seat depth as well. |
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Anything is possible when dealing with bullet 'jump Chamber, leade and throat all come into play. Quoted:
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seating depth tuning. Will show smaller group size when playing with different seating depths Anything is possible when dealing with bullet 'jump Chamber, leade and throat all come into play. |
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Quoted: so I am stuck with this accuracy? 55zmax RP brass KVB556M seated to mag length CFE223 26.5 shot 0.995" and 27 shot 0.775" http://i135.photobucket.com/albums/q138/astone6/DSC_0358-2.jpg Barrel length Profile Type of forend Stock trigger? Shooters skill
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Your rifle sounds fine, need to work on load. Start with match bullets. Headstamp matched brass trimmed to the same length, and go from there. I'm partial to AeroE's accuracy load; Win brass, Sierra 52 gr MK, 27.0 grs Re-15, Rem 7 1/2, OAL 2.250, no crimp. I uniform the primer pockets on my loads. I'm disappointed with more than 1/2, 5 shot 100 yd groups with this load.
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I have RP brass. All trimmed to same length. I weight sorted them long time ago too(not sure if it helps but I got bored one day)
I am trying the 69 SMK next. Just was curious if there was anything else to do with this combo to get it to shoot better. I have some Hornady 53 Vmax I bought few months back to try. Being a 9 twist and short barrel, I am limited to what heavy bullets I can shoot. Probably should find something more stable than grip pod as my front support |
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Quoted: I have RP brass. All trimmed to same length. I weight sorted them long time ago too(not sure if it helps but I got bored one day) I am trying the 69 SMK next. Just was curious if there was anything else to do with this combo to get it to shoot better. I have some Hornady 53 Vmax I bought few months back to try. Being a 9 twist and short barrel, I am limited to what heavy bullets I can shoot. Not true, My 1 in 9 barrel shoots the 52 gr MK load very well, so will yours. Probably should find something more stable than grip pod as my front support. Like a real sandbag, will make a big difference. |
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DPMS Oracle 16" 1-9 twist Quad rail Grip pod bipod rear rest Nikon 4-12x scope Geissele SSA E trigger Shooter skill- Sub 1/2" groups with bolt gun and 0.2"-0.3" with custom rifles shot off bench at 100 yards. (FTR/Fclass shooter) Get rid of that grip pod when testing loads. Shoot from a sandbag or something of that nature that is more stable. Your 1/9 should be fine for certain bullets up to 77g. If you can load them to mag length you should be fine as it is the length of the bullet not the weight that you have to worry about. If they are too long for your barrel then there is a good chance they can't be loaded to mag length anyways. 27g looked good on your targets. The fliers could be caused by how you are shooting because of the grip-pod. Change that first and re-shoot. |
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Being a 9 twist and short barrel, I am limited to what heavy bullets I can shoot. Not true, My 1 in 9 barrel shoots the 52 gr MK load very well, so will yours.
I was talking about heavy bullets. Maybe meant to type 69 SMK? I have some of those loaded and will test them this week and will shoot off more stable platform For the 55 Zmax and my gun holding groups sub 3/4" at 100 would be excellent. I would not even be too disappointed with sub MOA. But I think with reloads I should get better than MOA. Just getting into reloading for the AR. Sure is fun to shoot light recoiling AR vs my heavy kicking 308 FTR rifle 
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