question on 1:8 twist AR bull barrel & reloading

[elfster1234]

so I just got this 1:8twist cryo treated bull barrel EOP varmint rifle..... So far i'm rather happy with the cheap bulk box FMJ BT w/c 55grn bullets i've ran thru it.... i'm itching to try out some 75grn amax and 68grn BTHP match bullets.... just wondering if anyone has any experience here with these weights in 1:8 twist .223, which worked better, and with what powder / drop amount????

 

[Genius.]

Re: question on 1:8 twist AR bull barrel & reloading

24 gr of Varget pushing 75gr BTHP shoots sub MOA all day long.

It also likes 55gr Barnes TTSX also shoots extremely well for me.

I'm working on getting a load developed with 69gr SMK's and it's looking promising with 8208

 

[elfster1234]

Re: question on 1:8 twist AR bull barrel & reloading

that sounds really good and thank for the info.... i just picked up a 100pc box of 75gr hornady amax's for $17 bucks and i'm thinking 23.5 gr of varget... might do 5rounds each @ 24, 23.5, 23, 22.5, and 22... Thanks for the reply.


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: biggenius29</div><div class="ubbcode-body">24 gr of Varget pushing 75gr BTHP shoots sub MOA all day long.

It also likes 55gr Barnes TTSX also shoots extremely well for me.

I'm working on getting a load developed with 69gr SMK's and it's looking promising with 8208 </div></div>

 

[rgvt4]

Re: question on 1:8 twist AR bull barrel & reloading

My 1:8 rock river shoots the heavier bullets just fine

 

[Genius.]

Re: question on 1:8 twist AR bull barrel & reloading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: elfster1234</div><div class="ubbcode-body">so I just got this 1:8twist cryo treated bull barrel EOP varmint rifle..... So far i'm rather happy with the cheap bulk box FMJ BT w/c 55grn bullets i've ran thru it.... i'm itching to try out some 75grn amax and 68grn BTHP match bullets.... just wondering if anyone has any experience here with these weights in 1:8 twist .223, which worked better, and with what powder / drop amount???? </div></div>

With those 75gr A-max's you will need to load them singly, they are to long to seat for mag length.

That's why I run the 75gr BTHP's

 

[Temp9]

Re: question on 1:8 twist AR bull barrel & reloading

AMAX's are too long for mag length. Try Hornady 75gr HPBT if you want a high BC bullet. I'm loading the 77gr Nosler Custom Comp to about 2650fps with Alliant AR-C out of a 1:8 16" right now with great results. I'm planning to switch to the Hornady's soon for the increased BC.

 

[elfster1234]

Re: question on 1:8 twist AR bull barrel & reloading

thanks brother... i'll take these amax's back and get the hpbt.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Temp9</div><div class="ubbcode-body">AMAX's are too long for mag length. Try Hornady 75gr HPBT if you want a high BC bullet. I'm loading the 77gr Nosler Custom Comp to about 2650fps with Alliant AR-C out of a 1:8 16" right now with great results. I'm planning to switch to the Hornady's soon for the increased BC. </div></div>

 

[elfster1234]

Re: question on 1:8 twist AR bull barrel & reloading

returned the amax's and picked up a 100pc box each of 68grn and 75grn BTHP hornady.... really pumped about trying these out. thanks for the info.


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Temp9</div><div class="ubbcode-body">AMAX's are too long for mag length. Try Hornady 75gr HPBT if you want a high BC bullet. I'm loading the 77gr Nosler Custom Comp to about 2650fps with Alliant AR-C out of a 1:8 16" right now with great results. I'm planning to switch to the Hornady's soon for the increased BC. </div></div>

 

[USMC mustang]

Re: question on 1:8 twist AR bull barrel & reloading

I shoot Service Rifle Competition with a RRA NM with a 1:8 twist. My match loads have been 24.5 grs of RE-15 with 69 gr SMKs, 24 grs of RE-15 with 77 gr SMKs, and 23.5 gr of RE-15 with 80 gr SMKs. All are sub-MOA loads. FWIW, I find the performance of Nosler Custom Competition bullets in the same weight nearly identical to the Sierra bullets.

 

[3wide]

Re: question on 1:8 twist AR bull barrel & reloading

25gr varget and 77gr smk @ 2715 fps out of my 24in RRA bull barrel. Groups good at 100 but really stabilizes at 200+.

 

[Cegorach]

Re: question on 1:8 twist AR bull barrel & reloading

I have had good luck with the 75 bthp over 24 grains of Varget. Nothing exotic, but it has been a consistent performer for me.

This is out of a 20" 8 twist Armalite.

 

[Genius.]

Re: question on 1:8 twist AR bull barrel & reloading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Cegorach</div><div class="ubbcode-body">I have had good luck with the 75 bthp over 24 grains of Varget. Nothing exotic, but it has been a consistent performer for me.

This is out of a 20" 8 twist Armalite. </div></div>

That's the same load I run, and I run into a lot of guys who also find that load to be extremely accurate.

My barrel is a 18"

 

[shoot4fun]

Re: question on 1:8 twist AR bull barrel & reloading

I think, for best results in a semi, you should stick with the 75/77 HP. Some of those bullets are too long for reliable feeding from the mag unless seated so deep that you lose powder capacity.

 

[salmonaxe]

Re: question on 1:8 twist AR bull barrel & reloading

Personally I've had great luck with 77gr SMK's. I use ramshot TAC. Good velocity and takes less case volume. When I started getting close to a compressed load, using small rifle magnum primers brought my group size down. If I remember correctly, I'm running 24.5gr of TAC with CCI SR Magnum Primer. PMC brass(because it has a thick head and web, when I sectioned it.) 77gr SMK with cannelure. 2810ft/s from my High Caliber sales SPR bbl. (18" 1/7 twist).

I think that 7 twist is more fore really long bearing surface bullets or heavies like the 90gr SMK's. 8 should work great for stuff in the 75-77gr range.

A buddy had terrible luck with the hornady 75gr BTHP's. It looked like his issue was the seating stem just didn't interface well with the ogive of that specific bullet. Was pushing too far down the ogive, and giving inconsistent seating depths.

 

[RTH1800]

Re: question on 1:8 twist AR bull barrel & reloading

I shoot a bull barrel, 8 twist Baer with 77 grain SMK. Win or LC case, wolf primer and 24 grain Ramshot TAC. Stablizes well to 800 yards and groups are far better than MK 262 OTM.

 

[Captain Kirk]

Re: question on 1:8 twist AR bull barrel & reloading

Shoot plenty of 75gr Hornady HPBT and Sierra 77gr MKs out of a 1/8 with good results. 2000MR is a good powder if you want to push the heavy bullets fast.

Kirk R

 

[3wide]

Re: question on 1:8 twist AR bull barrel & reloading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Salmonaxe</div><div class="ubbcode-body"> If I remember correctly, I'm running 24.5gr of TAC with CCI SR Magnum Primer. PMC brass(because it has a thick head and web, when I sectioned it.) 77gr SMK with cannelure. 2810ft/s from my High Caliber sales SPR bbl. (18" 1/7 twist)</div></div>

Holy crap that's fast! You're doing 100 more fps, with a 6" shorter barrel than I'm using. Never thought of trying a magnum primer. Maybe I'll pick up some TAC.

 

[gmz71]

Re: question on 1:8 twist AR bull barrel & reloading

Im getting 2800 fps out of 25.2grs H4895 and a Hornady 75gr BTHP
DPMS MK12 barrel.
They group pretty decent.

 

[3wide]

Re: question on 1:8 twist AR bull barrel & reloading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gmz71</div><div class="ubbcode-body">Im getting 2800 fps out of 25.2grs H4895 and a Hornady 75gr BTHP
DPMS MK12 barrel.
They group pretty decent. </div></div>

The bad thing about varget is you run out of case capacity if your trying for more velocity. If I didn't already have 16lbs of it I'd be more serious about switching.

Hows your DPMS MK12 barrel group? I bought one about a year ago, assembled it, and am ashamed to say I haven't even shot it yet

 

[Temp9]

Re: question on 1:8 twist AR bull barrel & reloading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 3wide</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Salmonaxe</div><div class="ubbcode-body"> If I remember correctly, I'm running 24.5gr of TAC with CCI SR Magnum Primer. PMC brass(because it has a thick head and web, when I sectioned it.) 77gr SMK with cannelure. 2810ft/s from my High Caliber sales SPR bbl. (18" 1/7 twist)</div></div>

Holy crap that's fast! You're doing 100 more fps, with a 6" shorter barrel than I'm using. Never thought of trying a magnum primer. Maybe I'll pick up some TAC.</div></div>

Yup, that's blazing for an 18" barrel! I can barely break 2710fps using WS2 coated bullets. Granted, I'm using a 16" barrel, but I doubt I could get another 100fps from the 2" extra barrel length.

 

[salmonaxe]

Re: question on 1:8 twist AR bull barrel & reloading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Temp9</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 3wide</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Salmonaxe</div><div class="ubbcode-body"> If I remember correctly, I'm running 24.5gr of TAC with CCI SR Magnum Primer. PMC brass(because it has a thick head and web, when I sectioned it.) 77gr SMK with cannelure. 2810ft/s from my High Caliber sales SPR bbl. (18" 1/7 twist)</div></div>

Holy crap that's fast! You're doing 100 more fps, with a 6" shorter barrel than I'm using. Never thought of trying a magnum primer. Maybe I'll pick up some TAC.</div></div>

Yup, that's blazing for an 18" barrel! I can barely break 2710fps using WS2 coated bullets. Granted, I'm using a 16" barrel, but I doubt I could get another 100fps from the 2" extra barrel length. </div></div>

I think that with 5.56, 18" is the sweet spot. Anything shorter and velocity really drops anything longer and you're not really gaining much. Or at least that's what I've gathered from my own experience and seeing the results of that barrel chop test. Of course if you can somehow find a way to stuff more powder in the case, a longer barrel will help. TAC pretty much can achieve the highest velocities for 5.56 in all my reloading manuals. I think I'm about .5gr above max published by sierra.

My HCS SPR barrel definitely has a tight chamber. It seems to be in the neck area. I always run suppressed with my 12th model. And even though it runs well, I will have trouble manually extracting rounds after about 500rds. After about 1k, a carbon ring forms in the neck area, and creates pressure signs in pretty much all ammo I fire. (Popped primers mainly.) Then I need to use a chamber brush. With the way the chamber is spec-ed I think it just helps achieve a bit more velocity. When clean these loads don't show pressure signs, and when I plan on shooting them (vs. cheap stuff like xm193) I make sure to give the chamber a good cleaning. (But then I pass as few as possible patches through the bore to make sure all the debris is flushed out.)

But, I also get the same velocity (roughly) from my Compass Lake Engineering SPR barrel. It's pretty close to the HCS barrel, but has a midlength gas and a matched/headspaced bolt. Both are from Douglas blanks.

 

[elfster1234]

Re: question on 1:8 twist AR bull barrel & reloading

so far, i really like my 18" rock river EOP... totally agree with you! 18" to 20" is perfect for AR semi auto's!!! I'm running an 18" on my rock river and 20" on my LMT... Had a 24" on my old DPMS and is was just too much & heavy for my taste. Here is a pic of my 18" 5.56 that i'm developing the 5.56 ammo for. I got some low vortex rings in the mail, should have them on by the end of the week. Rocking medium rings right now just to get me by, but the new vortex low rings will get my scope to the same height as the larue LT104 mount. I'm really looking forward to it:

pic of RRA EOP 18" cryo SS bull barrel:

pic of my LMT and 20" CL:

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Salmonaxe</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Temp9</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 3wide</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Salmonaxe</div><div class="ubbcode-body"> If I remember correctly, I'm running 24.5gr of TAC with CCI SR Magnum Primer. PMC brass(because it has a thick head and web, when I sectioned it.) 77gr SMK with cannelure. 2810ft/s from my High Caliber sales SPR bbl. (18" 1/7 twist)</div></div>

Holy crap that's fast! You're doing 100 more fps, with a 6" shorter barrel than I'm using. Never thought of trying a magnum primer. Maybe I'll pick up some TAC.</div></div>

Yup, that's blazing for an 18" barrel! I can barely break 2710fps using WS2 coated bullets. Granted, I'm using a 16" barrel, but I doubt I could get another 100fps from the 2" extra barrel length. </div></div>

I think that with 5.56, 18" is the sweet spot. Anything shorter and velocity really drops anything longer and you're not really gaining much. Or at least that's what I've gathered from my own experience and seeing the results of that barrel chop test. Of course if you can somehow find a way to stuff more powder in the case, a longer barrel will help. TAC pretty much can achieve the highest velocities for 5.56 in all my reloading manuals. I think I'm about .5gr above max published by sierra.

My HCS SPR barrel definitely has a tight chamber. It seems to be in the neck area. I always run suppressed with my 12th model. And even though it runs well, I will have trouble manually extracting rounds after about 500rds. After about 1k, a carbon ring forms in the neck area, and creates pressure signs in pretty much all ammo I fire. (Popped primers mainly.) Then I need to use a chamber brush. With the way the chamber is spec-ed I think it just helps achieve a bit more velocity. When clean these loads don't show pressure signs, and when I plan on shooting them (vs. cheap stuff like xm193) I make sure to give the chamber a good cleaning. (But then I pass as few as possible patches through the bore to make sure all the debris is flushed out.)

But, I also get the same velocity (roughly) from my Compass Lake Engineering SPR barrel. It's pretty close to the HCS barrel, but has a midlength gas and a matched/headspaced bolt. Both are from Douglas blanks. </div></div>

 

[salmonaxe]

Re: question on 1:8 twist AR bull barrel & reloading

Nice sticks.

I've got a long bbl on my .308 AR. It's one of the old AR-10T's which had a 22" barrel. (or maybe it's 24") Anyway, it's really long and heavy, but since it shoots so darn well, I couldn't see changing it. Otherwise I think 20" is plenty good for a 308 semi auto.

Good luck with load dev.

Here's my AR-10T, it's a beast.

 

[gmz71]

Re: question on 1:8 twist AR bull barrel & reloading

It groups good enough for me in a semi auto platform. 1 moa is common.

 

[elfster1234]

Re: question on 1:8 twist AR bull barrel & reloading

you guys doing no crimp, light crimp?

 

[plant.one]

Re: question on 1:8 twist AR bull barrel & reloading

im doing no crimp on my 55gr vmax load for my 1:9 carbine and getting wonderful results.

i'll be curious to see what happens when i go to an 20" 1:8 woa barrel and start playing with load building

 

[3wide]

Re: question on 1:8 twist AR bull barrel & reloading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: elfster1234</div><div class="ubbcode-body">you guys doing no crimp, light crimp? </div></div>

No crimp here.

If I was using the cannaluer model 77gr smk I might.

 

[Eznutz]

Re: question on 1:8 twist AR bull barrel & reloading

For those of you using the TAC powder how do you find it burns as far as consistency in temp change? I'm currently using it to send 55gr noslers and it shoots sub moa and was thinking about using it for some 69gn smk. But I want to see how it faired in different temperatures with the snow beginning to fly i was going to do some load development.
If it varies extrememly i need to be wary of running a hotter load in the winter w/o pressure signs to the same load in the summer and was curious of any input.

thanks. and not trying to derail your thread.

 

[gmz71]

Re: question on 1:8 twist AR bull barrel & reloading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: elfster1234</div><div class="ubbcode-body">you guys doing no crimp, light crimp? </div></div>

No crimp.

 

[3wide]

Re: question on 1:8 twist AR bull barrel & reloading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Eznutz</div><div class="ubbcode-body">For those of you using the TAC powder how do you find it burns as far as consistency in temp change? I'm currently using it to send 55gr noslers and it shoots sub moa and was thinking about using it for some 69gn smk. But I want to see how it faired in different temperatures with the snow beginning to fly i was going to do some load development.
If it varies extrememly i need to be wary of running a hotter load in the winter w/o pressure signs to the same load in the summer and was curious of any input.

thanks. and not trying to derail your thread. </div></div>


From what I've read it is temp sensitive.

 

[Temp9]

Re: question on 1:8 twist AR bull barrel & reloading

No crimp with .003" neck tension. Be careful with some dies, as the expander ball is too big. My Lee FL die only gave me .001" neck tension.

 

[salmonaxe]

Re: question on 1:8 twist AR bull barrel & reloading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 3wide</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Eznutz</div><div class="ubbcode-body">For those of you using the TAC powder how do you find it burns as far as consistency in temp change? I'm currently using it to send 55gr noslers and it shoots sub moa and was thinking about using it for some 69gn smk. But I want to see how it faired in different temperatures with the snow beginning to fly i was going to do some load development.
If it varies extrememly i need to be wary of running a hotter load in the winter w/o pressure signs to the same load in the summer and was curious of any input.

thanks. and not trying to derail your thread. </div></div>


From what I've read it is temp sensitive.
</div></div>

From my experience it hasn't been temp sensitive. If it is, it's so subtle that it's had no major effect on my POI or pressure signs. I use RL-15 in my 6.5x47L and THAT is temp sensitive. About a foot a second per degree F increase in temp. Would suck in an autoloader.

Varget is about the least temp sensitive powder I've used. Ammo in the sun, rapid fire, letting a chambered cartridge sit in the chamber, none ever had any effect.

For my 300/221 I noticed that H110 is super temp sensitive too. Which sucks for heavies going subsonic. major vertical stringing.

 

[Eznutz]

Re: question on 1:8 twist AR bull barrel & reloading

Thanks for your input on the tac. I've just ordered a Chrony to check velocities and is should be here tomorrow. Im going to do some load work with the 69 smk and see what i come up with. thanks again.

 

[RTH1800]

Re: question on 1:8 twist AR bull barrel & reloading

To address the question of crimp, I do not do so but I do use a .243 bushing with a loaded round neck of 245.5 That seems to hold them well.
About TAC and temp sensitivity, find it very close to the MK 262 OTM specs on the cards that Kevin at HCS has. But I only shoot to 800 yards. I am going to work out some more data as it gets colder and compare with notes from the last two years. Basically, I think I add .1 mil for each 40 deg F drop. That is from memory.

 

[elfster1234]

Re: question on 1:8 twist AR bull barrel & reloading

going to set coal @ 2.26" / max pmag length for both 68gr and 75gr hornady bthp... what are you guys doing? just wondering... should be able to get a 30round shootout entry done, but i'm still doing load development...will not know the complete potential of the rifle until i find my pet load.

i did about 10rounds with 24.5, 20rounds 24.0, and 20rounds 23.5 varget on the 68gr bullets

and did about 10rounds with 23.5, 20rounds 23.0, and 20rounds 22.5 varget on the 75grn bullets.

should be run tomorrow. really looking forward to it.

 

[Temp9]

Re: question on 1:8 twist AR bull barrel & reloading

COAL 2.260" for almost all my AR loads, including 55gr Ballistic Tips. I haven't really felt the need to try otherwise since I'm already jumping about .040" anyways.

Be careful with charge intervals that large in a .223. It's possible that you'll completely skip over accuracy nodes. I like .2gr intervals for my initial workup (OCW) and .1gr intervals for fine tuning.

Something else to consider.... .223 Wylde chambers will show much less pressure (and therefore, much less velocity for equal charges) than .223 Rem chambers, which are what the companies use for their published load data. Therefore, you might want to work a little higher (watching for pressure signs, of course). My upper accuracy node for the 77gr NCC was 24.7gr VARGET in a 16" barrel. In an 18" barrel, I would expect your accuracy node to be around 24.1gr VARGET with the 75gr Hornady (around 2610fps if you have a chrono).

 

[elfster1234]

Re: question on 1:8 twist AR bull barrel & reloading

that's good information brother, thanks man.

I'll see if any of mine are more accurate with what i have now @ .5 apart, and then will lower charge rates down to .2 in that load area if i get an ultra small group. i already have them loaded up... will try the .2 next time. thanks bro.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Temp9</div><div class="ubbcode-body">COAL 2.260" for almost all my AR loads, including 55gr Ballistic Tips. I haven't really felt the need to try otherwise since I'm already jumping about .040" anyways.

Be careful with charge intervals that large in a .223. It's possible that you'll completely skip over accuracy nodes. I like .2gr intervals for my initial workup (OCW) and .1gr intervals for fine tuning.

Something else to consider.... .223 Wylde chambers will show much less pressure (and therefore, much less velocity for equal charges) than .223 Rem chambers, which are what the companies use for their published load data. Therefore, you might want to work a little higher (watching for pressure signs, of course). My upper accuracy node for the 77gr NCC was 24.7gr VARGET in a 16" barrel. In an 18" barrel, I would expect your accuracy node to be around 24.1gr VARGET with the 75gr Hornady (around 2610fps if you have a chrono). </div></div>

 

[KAZ]

Re: question on 1:8 twist AR bull barrel & reloading

A solid performer in several 8 twist ARs is CFE 223, and it deserves a try in yours. 24.1 in 77 smk and 27.5 in the 55 gn bullets. It flows perfectly from throwers and we have used cci 41 and rem 7 1/2 primers. Loaded to mag length. We have used it in 100 degrees plus and in 60s now. Regards