IM sent.................

Got it , thanks Kurt !

Just a little bit of an update on the .25-.223 AR.
Brent (320pf) hooked me into this one and to date I can't complain.  I'm finally getting the house in the hills finished and will be moving next week.  Since the house sits in the middle of 600 acres I wanted a "walk-around" rifle for utility duty that can could out perform the standard .223.  Brent came up with the reamer and we had a couple of Shilen barrels turned and chambered by Paladin Machine.  Following Kurt's (7.62x40) lead on his .25x40 the best results so far has come from 1680.

As has been explained before, the .wildcat is basically a .223 necked up to .25 and trimmed to 43mm.  Just about as simple as you can get.
The best results to date was from 22.0 grains of 1680 behind a 100 grain Speer bullet.  The velocity averaged 2529 fps for a 10 round string when measured 10' in front of the bench.  This is with a 16" barrel and the gas port in the carbine position.  No signs of over pressure at all.  

I tried a little IMR 3031 but the velocity stayed around a 2221 fps average with just about a full case.  I'll play with the 1680 a little more and try a few other powders after the move when my rifle range will only be a couple of hundred yards away.
But I wanted to thank both Brent and Kurt.  The threads by Kurt on his 7.62x40 got me started at looking at what can be done with the AR platform with nothing more than a barrel change.  Not being able to get a barrel and dies lead me to the .300 Fireball.  (I still want to try the 7.62x40!)  Brent was helping me with information on the Whisper/Fireball when he mentioned the .25-.223 and I had to give it a try.  Thanks to both of you and to the others that have taken part in the forum.
Terrill

I've had pretty good luck with H322 and 2230 using the 'heavies'.......

Kurt , am I seeing things?

The 6.8 in the top picture appears to have the shoulder and case OAL bumped up somewhat in contrast to the lower picture.

Just curious about the variation. If I were at the optometrist and he said "this one ,or this one ?" I would say "top" .

You're not seeing things...the early pic posted was from the revision using a body and neck reamer...also wanted to see how much neck it needed....the later pic is from a dedicated reamer...the shoulder is bumped forward and the  mouth moved a little (ratio wise)...good eyes...I usually have to use a comparator to catch stuff like that  

ETA. The dedicated reamer version is the one we're using now.......as discussed earlier, the case taper we use makes it easy to move the shoulder forward or back to experiment with length and not change the base opening much on the chamber ( .001 or .002)....shorter shoulder = tighter base....longer shoulder = open base.....as long as you stay within the tolerance of the die you're ok.....

had a question yesterday about using the 40*ish TCU dies with the 30* shoulder on the 6.8 and 7mm x40.....the TCU dies form the neck and body and don't touch the shoulder....I kinda like it like that....the headspace doesn't get bumped in, seems to help brass life when running the loads up....have been doing this for years with the bolt cats, using 40* Ackley Improved dies on 30* shoulder cats.....

Kurt , that's good to know. I was hoping that was the finalised incarnation.

I noticed that the earlier prototype had the shoulder riding about where a 222 would and the later was up closer to the 17 rem. which coincidentally is about where the shoulder would ride if you took an SPC case and turned it down to the .378 case size.

Also, nice tidbit about the TCU dies.

well....nothing I guess is ever final......the pics do show the two extremes..........the higher shoulder came about by tweaking that last little bit to hit 3,000fps.....ooops, I mean 2,900







really  ....the thing you run into with moving the shoulder too far forward along withmaking the body too long and straight with the size chamber base opening I like to use....is the body breaks over the chamber mouth before the round pops up while chambering....I usually creep things forward until I start seeing break-over marks on the body of the brass....there are things that can be done to smooth things out......

I have received several e-mails similar to this concerning the building of your own wildcat since the info was posted on the 6.8 and 7x40.....the 6, 6.5, 6.8, and 7mm are pretty easy to do because of the availability of 6, 6.5, and 7mm TCU dies...I usually get mine from Midway or direct from the manufacturer....I ordered (5) gold medal 7mmTCU dies from RCBS a week or so back and I haven't heard anythig so they may be short right now....

for making the dies I usually cut around .100" off the base of the sizer to get the length brass I want....

I usually make the dies up first before I chamber the barrel....the formed brass can act as a makeshift headspace gauge to get the depth chamber you want....

If you are going to get into having your own chamber reamer made, and plan to use the F/L TCU dies, the chamber reamer dimensions (shoulder width, taper, base, etc...) need to be similar to that of the TCU you are going to use.....

6.35.43mm (257/223) project update

I had a chance to try loading(W748 in the 25-223AR*
*.223 parent brass opened up to .25-cal; shortened to 43mm; maintains .223 body taper, same body shoulder junction height, does't require fire-forming.


Load Data: (standard disclaimer as with any wild-cat, use at own risk and work up slow) Note:  The powder was loaded into the case using an eight drop tube.  This facilitated a more dense/compact powder column.

100 gr Speer SPBT (16-inch barrel)

25.5gr W748 = 2350 fps
26.0gr W748 = 2411 fps
26.5gr W748 = 2435 fps
27.0gr W748 = 2475 fps
27.5gr W748 = 2510 fps
28.5gr W748 = 2548 fps

No signs of high pressure. Am interesting phenomena occurred with this load.  The ejected brass was was cool to the touch. The barrel was was only mildly warm after each five shot string.  SO this powder must burn pretty cool. There was NO powder residue in the barrel after each shot so W748 must also burn fairly clean.  In addition, all 30 round from this test grouped within 3-inches over the 200 fps velocity spread. I was not trying to shoot for groups.


I used the published loads for BL-C(2) in the 6x45mm found the Hodgdon reloading manual for a starting reference. The Hodgdon web site shows that  W748 is ranked at 82 and Hodgdon BL-C(2) is ranked at 83 on their burn rate chart.

For example Hodgdon lists:

6x45mm
85 gr SPR SP BL-C(2) (24" barrel)
Start: 25.5gr.-2566 fps; Max: 27.5gr.-2811 fps

90 gr SPR SP BL-C(2) (24" barrel)
Start: 25.05gr.-2523 fps; Max: 27.0gr.-2744 fps

100 gr HDY SP BL-C(2) (24" barrel)
Start: 24.5gr.-2404 fps; Max: 26.5gr.-2619 fps

320pf

I've tried to follow this thread, but the multiple calibers mixed together have got me confused (admittedly not hard).

Are there updates on the .277(6.8) x 40mm performance with load data?

Thanks!

Kurt,

Do you have any ballistic data on the 7x40mm?  I've got a set each of 6.5TCU and 7TCU dies sitting here.  I was thinking of having an AR barrel chambered in 6.5TCU until I stumbled across this thread.  Curious how the 6.8x40 and 7x40 compare.

Thnx!
Patrick

I'm working on having a couple sample barrels made.....spent a little range time today with the 6.5x40, 6.8x40, 7x40, and a few others.....compared the 6.8x40 and 6.8x41 for capacity and performance.....ran some 85 to 110gr projos.....I still like the 85s and 90s

as far as performance / load data....just what's here in the thread...

as with any wildcat, use load data at own risk......

6.8x40mm, 16", 1:10

90gr TNT 25gr 2230 = 2,485 fps
90gr TNT 26gr 2230 = 2,560 fps
90gr TNT 19gr 4227 = 2,485 fps
90gr TNT 20gr 4227 = 2,575 fps
90gr TNT 21gr 4227 = 2,708 fps
90gr TNT 22gr 4227 = 2,836 fps

7x40mm at the range....




I have a little info on the 7x40....I haven't pushed it as hard as the 6.8 yet....still fireforming brass and getting a little time on the barrel using the 110 TNTs and 120 BTBTs, I usually put a couple hundred rounds down the tube before I get on it too hard......the 6.5, 6.8, and 7 share the same body / shoulder junction, within a few thousandths of each other.....the shoulder on the 6.5 is a little longer than the 6.8 and 7.....

110 TNT 19gr 4227 = 2,280 fps
110 TNT 20gr 4227 = 2,480 fps


Left to right.....6.8x40, 6.8x41, 6.8 SPC, 7x40mm, 7x40mm





Just the initial testing, I've been pretty happy with the 6.8x40 with 85 and 90gr pills.....with the 6.5 and 7 TCU dies you could go either way.....comparing the 6.5, 6.8, and 7...with the available case capacity and using a 16" barrel, the 6.8 looks to be the most promising.....the 7mm 110 TNTs are a good bit longer than the 6.8 90 TNTs....sharing the same shoulder junction the 7mm 110 TNTs drop in a good bit past the shoulder and encroach on the capacity......but we have a fix for that too

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The 7mmARk

Hi Kurt :
What case is the The 7mm ARk based on, and can you give some of the specs on this cartridge.

Joe

That's sexy.................

Yeah, that is a damn fine looking cartridge right there...

All of Kurt's cartridges are purdy !

Thanks Kurt!  Curious, you mention "the 6.5, 6.8, and 7 share the same body / shoulder junction" - have you done this in a 6.5x40mm?  Like I posted above, I was thinking 6.5TCU until I came across this thread.  Bullet selection is better in the 6.8, esp. in the lighter weights, but I'm a little partial to the 6.5mm.  Not "married" mind you; just partial.



Seeing the 6.8x40 next to the 6.8SPC just gave me some dangerous thoughts.  What if you took the 6.8SPC, expanded it to 7.62, pushed the shoulder back to 40 degrees and shortened it to 40mm??  A little more case capacity than your 7.62x40 - maybe not enough to go to all that trouble tho'...

This wildcat stuff is contagious!

we've built one 6.5x40 and one 6.5x43....both were roughed in using the 25x40 cottonmouth reamer....both use shortened 6.5 TCU dies...the x43 is very close to the MPC....6.5 isn't one of my favorite calibers in the lighter bullets....I usually stay with the .25 under 100gr....

using the .223, SPC, and x39 Russian parent cases there are about 15 wildcats that I like....we've built 13 of the 15...

.223 case = 25, 27, 28, 30
SPC case = 25, 27, 28, 30, 338
x39 PPCish case = 25, 27, 28, 30, 338, 358

my favorite case length is 38 ~ 40mm.... I just like how most bullets in the weights I like to shoot lay-out in that length case, and fit in the mags....unless shooting heavy subs....

the 30/SPC you described is very close to Marty's 30HRT......I made a .30x40 SPC rendition a while back for a local shooter, close to what you described....the .223 based 7.62x40 with a 20" barrel and 1680 hit 2,600fps with 4gr less powder....

you're right it is contagious....with the BR case sized bolts on the horizon, Remingtons 30RAR, and other short magnums coming out there is plenty out there to keep busy with the 15 platform....that dosen't include the 10 platform or bolt-guns......

I've got enough to keep me busy through the winter until it's time to go offshore and chase tuna again....then the gun stuff gets put down for a little while....

It sure is!
320pf

Thanks guys....it's coming along....

The 7 ARk is laid out for 110 to 120grainers.....my favorites are the 110 TNT for punching paper and varmints, and the 120 Barnes for larger game....still working up loads but the Barnes at 2,700 is working out to 1,100 ftlbs at 300 yds....

was originally set up as a bolt-gun paper puncher, worked out ok so made a few changes and moved it over to the AR.....waiting on a 1:14 to loosen it up a little, but the 1:10s do work pretty good.....

will probably post some range pics this weekend....

Went to the range today to test a couple hunting loads.....

ended up going with the 85gr Barnes TSX and 1680 powder in the 6.8x40mm....

(as with any wildcat, work loads up slow, use data at own risk)


16" 1:10 barrel 20 round string average with 26.2gr of 1680 and the 85gr Barnes = 2,960 fps  ......I would consider right at 99% load density.....deviation was in the +/- 5fps range...


Accuracy was dead on with the  1:10 16" barrel.....squares on target are 1/2".....with the load set 1.5" high at 100yds put it about a 1/2" low at 200yds....right at 1000ftlbs of energy.....



5 shot group from a bi-pod.....

Thanks for the update.

Man that looks good , the anticipation is killing me !

RCBS has started shipping TCU dies again so that helps.....

Kurt , you win page 6. (it is your thread)

I'm going to entertain you with my build now ,

I've got a CavArms MKII that I'm going to chop 1", might even cut out the trigger guard and epoxy in an enhanced trigger guard.

I'm trying to talk myself out of an ASA side charger.

Definitely going to have Troy TRX Extreme 11" forend

At some point I'd like to add a Ben Cooley brake.

Magpul 20rd P-mags

Add MBUS and a indeterminate optic and I'm done



ETA- wait !  I'd also like a MartyW  snow leopard paint job !

Sounds like a great walker / stalker .......

I'm going to send along the A2 flash hider that was on it, it's a 1/2x36, most everything else I have is 5/8x24, so it was kinda specific to that barrel for me....

I've had better luck with the 30rd pmags....or 20rd ones with 30rd followers in them....you drop a couple rounds in the capacity due to the longer follower but they feed a lot better.....

should have a bow tied around several projects before the Holiday....

Got a little range time with the 7mmARk today, sorry for the crappy cell phone pics....forgot my camera at home




7mmARk, 18", 1:10 twist






worked up a few loads with the 110 TNT using 1680 and 2230 powders....

Standard disclaimer, as with any wildcat use reloading data at your own risk.

110gr TNT 25gr 1680 = 2,515 fps
110gr TNT 26gr 1680 = 2,660 fps
110gr TNT 27gr 1680 = 2,750 fps
110gr TNT 28gr 1680 = 2,860 fps

110gr TNT 30.5gr 2230 = 2,725 fps
110gr TNT 31.5gr 2230 = 2,795 fps
110gr TNT 32.5gr 2230 = 2,904 fps    ( right at 320 power factor with a 110 )

This set-up really likes the 2230....at 2,900 fps I fired several five shot groups that the majority of the groups were cloverleafs.....



7mmARk,  6.8 SPC,   6.5 Grendel


The 7mmARk is formed from 7.62x39 Russian or 6.5 Grendel brass.......feeds perfect from C products 6.5 Grendel or 7.62x39mm mags.....


In comparable platforms and hunting test range, the 7mmARk is outperforming both my 6.8 SPC and 6.5 Grendel.....it has more capacity than the 6.8 and less bore pressure than the 6.5

the loads of 2230 at 2,900fps exhibited no signs of high pressure ( ejector / extractor swipes, extruded brass, extruded primers, etc.....)

Got a couple calls from people wanting to know what I am using for dies and bolt with the 7ARk....I have two different sets of dies....and a couple bolts....

one sizer is made from a RCBS Gold Medal Match 6mmPPC neck bushing die, the neck hole is opened up and uses a .304 neck bushing and a 7mm tapered expander...this die works but is a little shorter than I like....doesn't fully size the base...

the other sizer is a Redding 6.5 Grendel neck bushing die shortened a little to square off the base, the neck hole is opened up and uses a .304 neck bushing and a 7mm tapered expander...

both are close enough to get the brass fire-formed.....after it's fire-formed the Redding die resizes the base and neck perfect, and slims the shoulder just enough that resized brass just drops in the chamber....

Using a 7.62x40mm seater die with a 7mm plug......


No special bolt, just using a DPMS and Olympic.....I did spend a good bit of time setting and lapping the extension / bolt lug back-side....in their original condition neither bolt had full lug to extension contact, may be a contributor to some of the broken bolts seen in other threads.......I run some pretty stiff loads with the 7.62x39, 7mmARk, 30ARk, 338ARk, 358ARk using the same bolts....at around 1,100 or 1,200 round count on each, no broken bolts.....

 
The 280 Kurt's ?  

7ARk = 7mm AR platform kalashnikov    ( uses 7.62x39 russian brass )

or

7ARk = 7mm AR platform kurz    ( uses shortened 7.62x39 russian brass )

or

7ARk = 7mm AR platform kurtz    ( quazi kool possessive   )

went to the range today and tested more loads for the 7ARk and did some comparison with the 30ARk and 7.62x40mm.......

As with any wildcat, use reloading data at your own risk.

100gr Sierra Varmint 26gr 1680 = 2,690 fps
100gr Sierra Varmint 27gr 1680 = 2,825 fps
100gr Sierra Varmint 28gr 1680 = 2,895 fps
100gr Sierra Varmint 29gr 1680 = 2,950 fps
100gr Sierra Varmint 29.5gr 1680 = 3,030 fps

110gr Barnes TTSX 28.5gr 1680 = 2,820 fps
110gr Barnes TTSX 29gr 1680 = 2,875 fps
110gr Barnes TTSX 29.5gr 1680 = 2,920 fps



7ARk,  6.8 SPC,  .30ARk




Compared a few loads between the .30ARk and 7.62x40mm in 20" barrels....

.30ARk
125gr TNT 27gr 1680 = 2,480 fps
125gr TNT 28gr 1680 = 2,560 fps
125gr TNT 29gr 1680 = 2,653 fps

7.62x40mm
125gr TNT 26.5gr 1680 = 2,620 fps

The .30ARk isn't as efficient as the 7.62x40mm with the lighter bullets.....but with bullets over 130gr the ARk pulls ahead.....more on that later.....

Kurt -

If the 7.62x40 is more efficient than the 30 ARk, would it be a reasonable assumption that the 7 mm versions have a similar relationship?

Also, do you have any results with the 120 gr bullets in the 7 x 40?

Hi Marty,

Today was a short day, I got your e-mail on the way out......

I guess efficiency can represent several different things depending on what you're chasing.....economic impact, most ft lbs of energy, least amount of fuel to do the most amount of work, etc.....

I used two platforms that I have intimate knowledge of the chambers and barrels.....I like to think from the neck forward they are pretty evenly matched and mechanically friendly....

we're talking about two cartridges that are only separated by 6 or 7 grains of usable capacity with 1680 and about .060 thousandths of an inch difference in case diameter to bore ratio.....the 125 TNTs are popular and common for intermediate cartridges.....and the 1680 powder is also a known good performer in intermediate cartridges.....

If you hold the powder charge fixed at 26.5 grains the ARk is going to produce ~ 2,425 fps compared to the x40 at ~ 2,625 fps ....... can the ARk be pushed harder to surpass the x40.....sure it can....but what I believe it does illustrate is the amount of compression that takes place in the ever so slightly larger volume cartridge, even though the difference in capacity is so little and the rest of the platform is evenly matched......now do the same test comparing the x40 to something the size of a .30-06 where the cases are separated by over 35 grains of capacity....even more compression and lower performance.....

I believe it also illustrates how much more 'fuel' the slightly larger volume case requires to create the same amount of work....in this case a 125 TNT at 2,600 fps the x40 required 2.5 grains less 'fuel' than the ARk.......you could chase it back to economics and say you would get 23 more rounds of loaded ammo per pound of powder and get more   " bangs for the buck "

I saw similar results with the 6.8x40 and SPC, even though the difference in capacity is smaller, the 6.8x40 will push a 90gr TNT to 2,900 fps with ~ 2 gr less powder....can the SPC push a 90 TNT faster ?.....sure it can....

one would think that the 7x40 and 7ARk would follow the same logic.....I guess my answer right now is I don't know for sure, haven't run them heads-up......the 6.8x40 and 7.62x40 have the luxury of the flat base 90 and 125 TNTs stopping at the neck / shoulder junction, whereas with the 7x40 the 110 TNT drops in past the neck / shoulder junction a good bit, the 120s are even worse,   into the usable capacity.......so you can't hit the 26.5 grains of 1680 like the others......If you can't tell I really like 1680....I set a lot of my stuff up around it.....it's easy.....pretty forgiving......and I got LOTS of it.....I'm in the process of cutting back the 7x40 a couple inches and will end up running something a little hotter than 1680 to make up for the encroachment.....

I've come up with some basic set-ups based on the average case volume / bore size / TNT bullet weights / using 1680 powder that works for me....

.30 cal likes 20" barrels 125gr
.28 cal likes 18" barrels 110gr
.27 cal likes 16" barrels 90gr
.25 cal likes 14" barrels 87gr

are they the end all be all set-ups? probably not.......but shit man, I get tired of making barrels.....I'm starting to look at barrels like disposable razors....whatever's on sale and cuts what I need to cut.....

KB

More range results with the 7 and .30  ARk......

As with any wildcat, use reloading data at your own risk.


7ARk ( 120gr BTBT )         .30ARk ( 125 BTBT )



7ARk
120gr BTBT 27gr 2230 = 2,230 fps
120gr BTBT 29gr 2230 = 2,440 fps
120gr BTBT 32gr 2230 = 2,675 fps     321 power factor

.30ARk
125gr BTBT 27gr 2230 = 2,030 fps
125gr BTBT 30gr 2230 = 2,350 fps
125gr BTBT 32gr 2230 = 2,510 fps




7ARk ( 110 TTSX )         .30ARk ( 110 TTSX )



7ARk
110gr TTSX 32gr 2230 = 2,710 fps
110gr TTSX 28.5gr 1680 = 2,810 fps
110gr TTSX 29gr 1680 = 2,870 fps
110gr TTSX 29.5gr 1680 = 2,919 fps  

.30ARk
110gr TTSX 32gr 2230 = 2,450 fps
110gr TTSX 26gr 5744 = 2,508 fps
110gr TTSX 27gr 5744 = 2,600 fps





7ARk
162gr AMAX 21gr 5744 = 2,080 fps      336 power factor
162gr AMAX 22gr 5744 = 2,166 fps      350 power factor
162gr AMAX 23gr 5744 = 2,208 fps      357 power factor
 

.30ARk
135gr SMK 25gr 5744 = 2,354 fps
135gr SMK 26gr 5744 = 2,435 fps      328 power factor
135gr SMK 27gr 5744 = 2,525 fps      340 power factor

155gr SMK 22gr 5744 = 2,040 fps
155gr SMK 23gr 5744 = 2,150 fps      333 power factor
155gr SMK 24gr 5744 = 2,240 fps      347 power factor






ETA..fix copy paste screw-ups

No problem, got it today.....may launch tomorrow

I made up some loads for the 6.8x40mm about a week ago using 85 Barnes and 1680, they were clocking a tic over 2,900fps in 40* weather....I loaned the rifle to a friend to use on a East Texas hog hunt....hopefully we'll get some pics....

Wishing you and your family a Merry Christmas and a Happy New Year,

KB

That's great news Kurt ,  I appreciate your help.

Merry Christmas & Happy New Year to you and your family as well

GB

It came today and it is beautiful!

Now I can get started on getting "my precious" together.

Thanks again Kurt.      

That's great....glad you're happy with it.....

Are you still going to use a TRX Extreme handguard?.....have you ever used one before?.....have a local shooter that I'm working on another wildcat for and I should have one of the carbine TRX Extremes here in a day or so to put on it if you want some feedback on it....looks like a nice light handguard......

I set the 6.8 dies up using my shellholder that measures .123 from the face to the shoulder, so you may need to adjust the sizer a little depending on your shellholder and ram.....

Happy New Year.....

Kurt,

I've been playing with my CAD and the 7mm TCU cartridge dimensions for a couple weeks.  That first picture above has been puzzling me.  The 7mm TCU shoulder starts at 1.450".  Taking .10" off the die should push the start of the shoulder down to 1.350".  With the 40 degree shoulder, that leaves about .175" for the neck on the 6.8mm with the case length at 1.565".  

Does that sound right?  If so, that's about 63% of caliber.  Most cartridges have neck lengths closer to caliber diameter.  For example, the 7mm TCU is spec'd at .253"(89% of caliber).  Looking at the photo above, the neck appears longer than .175", but online pic's can be deceiving.

I'm certainly not doubting your results - just checking my math.

Thanks!
Patrick

Hey Patrick,

no prob, GD and I talked about the pics a couple pages back I think.......I'm gonna give you the die lengths, that's just how I record them, we've set the 6.8 up using dies between 2.3" and 2.4" long.....and the chambers uses a 30* shoulder.....

the 2.3" die puts the start of the fire-formed shoulder at ~ 1.285 "  case length ~ 1.565"
the 2.4" die puts the start of the fire-formed shoulder at ~ 1.375"  case length ~ 1.655"

With the .277 cal I usually run my necks between .200" and .210" ....not sure what the % of caliber is on that right now, don't feel like thinking that hard unless I'm at work....but  I usually figure the necks around 75 to 80% when drawing chambers.....

the pics....the neck in the pic looks shorter than I usually run....when I'm testing chambers in the field there are times I may hand ream between .010 to .050" on the chamber experimenting with length while I'm at the range......if it's done in .003 to .005" increments the same brass can be used walking the shoulder forward each fire-forming, but the neck does get shorter, sometimes in the 50% range while experimenting.......so it's a pretty good chance you'll see neck lengths all-over-the-place when comparing my pics....I experiment a lot......more than I post.....

We've done 6.8s between 40 and 42mm.....I like the x40.....In this caliber I shoot a lot of the 90 TNTs, I like where the base of the bullet lays at 2.250 COAL.....

I've been pretty happy with the 90TNT at 2,900fps on a .223 case....I've pushed it harder, but it already gives my SPC buddies fits doing it with 2gr less powder.....

KB

I thought the 7mm TCU had a 40* shoulder??

http://stevespages.com/jpg/cd7tcu.jpg



OK - much better.  I follow you now!  At least with regard to neck length.  I'm still confused on shoulder angle...

Thanks again!
Patrick

The 7 TCU does use a 40* shoulder.........this isn't a TCU........it uses a 30* chamber and a 40* die........when resizing, the die slenders the shoulder width slightly; sizes the base; sizes the neck; bumps the neck shoulder datum point back a tiny bit; but doesn't push the shoulder face back.....think of it like a combination of neck and full-length sizers.....I do something a little different on my chambers that allows the use of the 40* dies and still get ~ .002" case / chamber free-fit, like you would full-length sizing a .223 or someting for a auto-loader.....

Steve may not like his images being copied, ...........he's been known to block ISPs.....ask me how I know

Still plan on using the TRX , hadn't had any personal experience with it so any feedback is welcomed.

I think it will suit the theme of "simple,clean, and light" with my CavArms lower well , also like the slim profile.

I'm savoring every bit of my 6.8x40 build . .

sounds like a great light-weight set-up.........the TRX looks like a sweet handguard, I like the idea of it being a little smaller than a standard tube, more of a stg44 grip size ....may also work with a sub-project gas block I've been working on......

keep us updated............

4AM is gonna come soon, I'm out...........

KB

I hate to butt in, but what is the consensus guys? what caliber should I get my next AR chambered in and where can I find the barrel, dies, etc.?  I really like the .25 x 40 concept.

I get up at 5 AM myself, so I better get outa here as well.

Indy

OK - I made the (mistaken) assumption that, since you were using TCU dies, that you were retaining the shoulder angle.  Not asking you to give up any trade secrets, but curious why you favor the 30* shoulder?


Oops!!  Fixed it.  I totally understand the problem with remote servers burning bandwidth....

A little info on the TRX carbine.....comparing it to a JP VTAC carbine....

The TRX is 7 5/8" long and weighs 7.5 oz with barrel nut.......nice touches, free CQB sling, included barrel wrench, 3 rails and hex wrench

The JP is 7 1/8" long and weighs 10.7 oz with barrel nut.....included 2 sling studs and hex wrench.

For the build I'm working on I'll probably have to go with the JP due to not using a low-pro gas block.....the TRX extends about .5" over the gas block seat shoulder......

The finish on both are top shelf......

give us an idea of what you are thinking about using it for.......plinking, hunting, etc......

I've been talking with someone about doing some .25 barrels, one of the issues with a lot of wildcats are the dies....the Hornady .25 dies I had made are superb, but they take a while to get due to the industry backlogs.....one of the reasons I've been doing work with the TCU dies, easier to get.....I've got the die parts on the bench to put together a set for the .25 to try out, just working on other projects......