6mm arc PRS gas gun division

[Possum_Puncher]

I’m in the process of doing 6arc testing with 20” and 22” barrels. 1:7 twist. This will be for PRS gas gun division. I see many posts on 6mm arc and I’m wondering why I’m not seeing solid groups (1/2 moa or better) I want to shoot 105-109gn projectiles. I’m going to hand load. What success does anyone have with this? Post your groups, let’s talk.

 

[db2000]

1/2 MOA gas gun groups?
As in 10 shot groups?
Good luck with that.

 

[Rudy Gonsior]

I’m in the process of doing 6arc testing with 20” and 22” barrels. 1:7 twist. This will be for PRS gas gun division. I see many posts on 6mm arc and I’m wondering why I’m not seeing solid groups (1/2 moa or better) I want to shoot 105-109gn projectiles. I’m going to hand load. What success does anyone have with this? Post your groups, let’s talk.

I think your expectations are on the upper end of what is realistically possible. 1/2 MOA gas-guns are rare things, 1/2 MOA shooters are equally few and far between.

What components are you working with?

 

[MaximusDecimusMeidius]

1/2 moa?

You could darn near win every f class match you entered if you could hold .5moa every grouping

 

[tjcazes]

Boy boy boy this is gonna hurt peoples feelings and I can’t wait to follow along.

 

[tjcazes]

I think your expectations are on the upper end of what is realistically possible. 1/2 MOA gas-guns are rare things, 1/2 MOA shooters are equally few and far between.

What components are you working with?

We have unlimited resources so to speak on this project. Alpha brass, Berger hybrids and a plethora of powders to test will be the foundation.

1/2 moa gas guns are easily attained these days with a good barrel and hand loads so I don’t foresee this being an issue. This post was more to compile a list of all the combinations of projectiles/powder/primer/brass combos people have tried not just the ever boring “leverlution and varget git ma vote” comments. Yea. We get it. You read a recipe on the internet and ran with it.

This is more to see what has been tried. What has failed and what has succeeded. Where can we build on this etc. we know lever works and is just dirty so it will get tested further but I digress.

Quality barrel manufacturing and machining is more common than most gas gun folks give credit for or are willing to pay for I guess but we have barrels that will shoot. That’s not an issue. I just want to test every single combination I can without going down a road that has failed before.

I’ll be modeling a lot on grt to get things going but as a whole we just wanted to get a thread with usable information from people who have actually put forth an effort into a caliber with seemingly subpar factory options. I know this is a public forum so pour on the “use the search function” “this has already been discussed” etc etc. that’s fine. Contribute or don’t. Those posts still keep the thread at the top and easy to find lol.

 

[db2000]

Here’s two random 10 shot strings I found. A Shaw SS barrel I sold and my Proof CF. Seekins builds. Both 18” probably me with the fliers but who knows. 1 MOA would be awesome, 1/2 is unrealistic.

 

[supercorndogs]

If that's all it's for there is already a 6 arc thread for that........in the............wait for it..........reloading section.

 

[Possum_Puncher]

I think your expectations are on the upper end of what is realistically possible. 1/2 MOA gas-guns are rare things, 1/2 MOA shooters are equally few and far between.

What components are you working with?

Right now it’s just factory ammo. Same uppers I’m using on my 1/2 moa 223 gas guns. The barrel is solid. It’s grouping like that with all the barrels I’ve seen. About an inch

 

[Possum_Puncher]

Here’s two random 10 shot strings I found. A Shaw SS barrel I sold and my Proof CF. Seekins builds. Both 18” probably me with the fliers but who knows. 1 MOA would be awesome, 1/2 is unrealistic.
View attachment 8473911

View attachment 8473912View attachment 8473917

I heard the Shaw was solid. Were these factory or hand loads?

 

[Possum_Puncher]

If that's all it's for there is already a 6 arc thread for that........in the............wait for it..........reloading section.

if only there were. The search button on mine is wore out. All I see is light bullets, or 105 with lever and no posted groups. I find posts asking the same shit redundant too but I’m not finding answers. The bolt gun guys are doing great but not a lot of gas gun with heavies info that I’ve seen.

 

[Possum_Puncher]

We have unlimited resources so to speak on this project. Alpha brass, Berger hybrids and a plethora of powders to test will be the foundation.

1/2 moa gas guns are easily attained these days with a good barrel and hand loads so I don’t foresee this being an issue. This post was more to compile a list of all the combinations of projectiles/powder/primer/brass combos people have tried not just the ever boring “leverlution and varget git ma vote” comments. Yea. We get it. You read a recipe on the internet and ran with it.

This is more to see what has been tried. What has failed and what has succeeded. Where can we build on this etc. we know lever works and is just dirty so it will get tested further but I digress.

Quality barrel manufacturing and machining is more common than most gas gun folks give credit for or are willing to pay for I guess but we have barrels that will shoot. That’s not an issue. I just want to test every single combination I can without going down a road that has failed before.

I’ll be modeling a lot on grt to get things going but as a whole we just wanted to get a thread with usable information from people who have actually put forth an effort into a caliber with seemingly subpar factory options. I know this is a public forum so pour on the “use the search function” “this has already been discussed” etc etc. that’s fine. Contribute or don’t. Those posts still keep the thread at the top and easy to find lol.

Yes

 

[Possum_Puncher]

1/2 moa?

You could darn near win every f class match you entered if you could hold .5moa every grouping

Shit a solid PRS gun should be 1/2. If my 223 gas guns can do it. It too much to ask for 6arc?

 

[Possum_Puncher]

1/2 MOA gas gun groups?
As in 10 shot groups?
Good luck with that.

The 223 builds will do 1/2 with 5 and 10 to 5/8 all day. With factory. I just want the 6arc to do better than the occasional 1”

 

[supercorndogs]

if only there were. The search button on mine is wore out. All I see is light bullets, or 105 with lever and no posted groups. I find posts asking the same shit redundant too but I’m not finding answers. The bolt gun guys are doing great but not a lot of gas gun with heavies info that I’ve seen.

Oh I see. I am sure now that you asked the same shit redundant question again everyone will have the answers you want.

Probably the fact most shooting heavies are using lever is called a clue.

 

[Possum_Puncher]

Oh I see. I am sure now that you asked the same shit redundant question again everyone will have the answers you want.

Probably the fact most shooting heavies are using lever is called a clue.

It would be if they were getting results. All good results I’ve seen are from loading longer in bolts. Just wondering if anyone has with a gasser. But I tell ya what. Go digging and find the answers to what I asked in the post in the reloading thread and I’ll send you a free sticker. It would save a lot of time

 

[supercorndogs]

It would be if they were getting results. All good results I’ve seen are from loading longer in bolts. Just wondering if anyone has with a gasser. But I tell ya what. Go digging and find the answers to what I asked in the post in the reloading thread and I’ll send you a free sticker. It would save a lot of time

Oops my bad. The "6mm advanced rifle cartridge" thread is not in the reloading section. It's in the semi auto section. I would post a link but I am afraid you would try to send me a sticker.

 

[Possum_Puncher]

Oops my bad. The "6mm advanced rifle cartridge" thread is not in the reloading section. It's in the semi auto section. I would post a link but I am afraid you would try to send me a sticker.

Cmon it’s a super cool sticker

 

[supercorndogs]

I will post a link but you have to sign a contract not to try send me a stickers. I will have ma lawyer write something up. It might take a couple days. I dont think there is any boilerplate for this.

It's right at the top in the stickies. not tons of info. It's a niche cartridge thats even more niche in gas guns. There is lots load data via hornady and hodgdon. The smaller case tends to perform well with an energy dense ball powder. Lever, cfe223, 2520.

I think the fact that most grendel shooter don't shoot 140s is clue that the 6 arc might be better with something a step or two down from the heaviest heavey.

 

[Possum_Puncher]

I will post a link but you have to sign a contract not to try send me a stickers. I will have ma lawyer write something up. It might take a couple days. I dont think there is any boilerplate for this.

It's right at the top in the stickies. not tons of info. It's a niche cartridge thats even more niche in gas guns. There is lots load data via hornady and hodgdon. The smaller case tends to perform well with an energy dense ball powder. Lever, cfe223, 2520.

I think the fact that most grendel shooter don't shoot 140s is clue that the 6 arc might be better with something a step or two down from the heaviest heavey.

I appreciate the info. I just wish you’d reconsider the stickers. I’ll have my lawyer talk to your lawyer

 

[supercorndogs]

1/2 moa?

You could darn near win every f class match you entered if you could hold .5moa every grouping

If there was a 100 yard class for centerfire rifles,1/2 moa wouldn't place....

 

[Ledzep]

I got 2nd place in Gas gun for the season last year with a 24" Bartlein 1:7.5" bull barrel in 6mm ARC. If I recall it was within 5 points on the match and came down to a single stage that Jeff beat me with his 22 CM. Cartridge/rifle wasn't the determining factor IMO-- Jeff shot a better match.

At any rate, here are a couple of test strings from development of that system. Bear in mind these are at 200yd so cut in half for MOA. ETA: Also bear in mind I don't usually take the time to update environmental data in the Oehler system so the displayed BC's are not necessarily accurate.

Was messing with the factory 108 Match powder (similar to LVR) and 110 Atips. Didn't like the velocity spreads and didn't run it.

15 shot string with book max charge (gas gun data) of Varget and 110 A-tip. This ran slow but was what I ended up taking to the finale.

20 rounds of Factory 108 Match. Ran this early in the season at Cameo.

 

[Possum_Puncher]

Thank you! This is solid info

 

[Ledzep]

In my opinion, you can reasonably expect 3/4 MOA from a gas gun for 20 shot strings and to get much better than that the stars have to align. This is from a bench, bipod and bag with consistent fore-end loading. There are a bunch of sub-1/2 MOA 5-shot groups in what I just posted above but that isn't indicative of the capability of the system. It was a 3/4-1 MOA rifle that could have the MPOI pushed around by as much as .3-.8 mils depending on handguard loading-- which is the real weak point of the gas gun game. I have shot 3/4 MOA bolt guns in the same style matches and finished top 20 or even top 10. The MPOI movement made my gas gun finishes in the 60th-90th place range.

 

[Possum_Puncher]

I got 2nd place in Gas gun for the season last year with a 24" Bartlein 1:7.5" bull barrel in 6mm ARC. If I recall it was within 5 points on the match and came down to a single stage that Jeff beat me with his 22 CM. Cartridge/rifle wasn't the determining factor IMO-- Jeff shot a better match.

At any rate, here are a couple of test strings from development of that system. Bear in mind these are at 200yd so cut in half for MOA. ETA: Also bear in mind I don't usually take the time to update environmental data in the Oehler system so the displayed BC's are not necessarily accurate.

Was messing with the factory 108 Match powder (similar to LVR) and 110 Atips. Didn't like the velocity spreads and didn't run it.
View attachment 8474285

15 shot string with book max charge (gas gun data) of Varget and 110 A-tip. This ran slow but was what I ended up taking to the finale.
View attachment 8474287

20 rounds of Factory 108 Match. Ran this early in the season at Cameo.
View attachment 8474289

Thank you this is solid info

 

[st1650]

If you don't care about barrel life go with N540 ... more temp stable than LVR and will give you more speed than Varget.

 

[tjcazes]

If you don't care about barrel life go with N540 ... more temp stable than LVR and will give you more speed than Varget.

Can you elaborate on this?

 

[Hecouldgoalltheway]

I have been amazed at the Accuracy I've gotten from 6arc gas guns. I was an early adopter, been shooting them since they announced them. I've assembled a dozen of them by now for myself and friends, and every single one of them shoot sub moa with about anything that's safe to put into them, including all available factory offerings. I can't say that any of them are consistent .5moa shooters since I'm probably not good enough to make that happen myself, but .75moa is easy with occaisonal one hole groups. Whoever said anything about shooting 140's in a Grendel doesn't understand the cartridge, nor the modifications made to the Grendel case to make the arc.

I also want to point out that .5 moa in prs is absolutely unnecessary. I've never seen a single target in any match I remember shooting that was smaller than 1moa. In every match I've shot, if you shot 1 moa all day they would call you the winner and place a garland of flowers around your neck and award you three virgin slaves, or whatever they give you when you win, I've never bothered to stick around to find out.

 

[supercorndogs]

Can you elaborate on this?

I would guess it's throat burner like Varget maybe? No exeperice with any VV powders.

 

[st1650]

Can you elaborate on this?

LVR and CFE223 aren't temp stable and generally aren't super consistent for velocities even if you can get a load to shoot fine at 100y, your SDs/ESs will suffer at long range.

Varget is perfectly fine with the 6ARC but because it's a bit too fast burning, you'll hit pressure way before you get decent speed.

The only current temp stable powder that gives you the 95-100% casefill and proper burn for the family of heavy 6.5 grendel and 6 ARC is N540. It'll give you a good 150-200FPS over varget with the same accuracy and temp stability.

The problem with N540 is that it's double base and higher energy and will cause premature throat erosion. How much is debatable but a quick search of N540 throat erosion and you'll find dozen of topics on the matter.

If money is no object and you have a few barrels to burn and are looking purely at performance then it's the right choice in my opinion. That's what I use in my 6.5 Grendel hunter with Speer GD 120 since I run it as a very low usage carbine.

 

[supercorndogs]

As you drop down in bullet weight those powders that are a little on the fast side 105-110. Become a little less on the fast side.

 

[Ledzep]

6mm ARC is pretty forgiving for barrel life anyway. I've pushed 60,000psi Varget/110 loads for 4500 rounds and pulled the barrel because I was scared, not because it stopped shooting. Have run 3500 rounds on another barrel that's still shooting well, and we have a collective barrel that has ~5000 rounds on it now (mix of factory and Varget loads) and still shooting. Our friends in the DoD have take gas gun barrels over 7000 rounds and maintained acceptable accuracy for their purposes (maybe not match shooting purposes). Pulled my gas gun PRS barrel at ~3000 rounds and gave it to a co-worker.

At any rate I'd say 4000-5000 is probably going to be pretty standard for decent PRS use.

 

[MaximusDecimusMeidius]

how does 6.5 staball and also staball match do with 6 arc

i stocked up both of those and 108 eld-m's for when my proof 14.5" barrel gets here

 

[loclass]

how does 6.5 staball and also staball match do with 6 arc

i stocked up both of those and 108 eld-m's for when my proof 14.5" barrel gets here

Staball 6.5 is not a good match for 6arc.....too slow. Staball match has potential.

 

[MaximusDecimusMeidius]

10-4. It will be a while before I start working up loads. Haven't received my proof 14.5" 6ARC yet and I have bought a thousand rounds of factory 108 eld-m just for the brass

I'm stocked up on 108 eld-m projectiles and have tons of bergers left over from my 6 dasher bolt action prs days

i've gone 100% gas gun now though

 

[MaximusDecimusMeidius]

 

[Conrad]

I got 2nd place in Gas gun for the season last year with a 24" Bartlein 1:7.5" bull barrel in 6mm ARC. If I recall it was within 5 points on the match and came down to a single stage that Jeff beat me with his 22 CM. Cartridge/rifle wasn't the determining factor IMO-- Jeff shot a better match.

At any rate, here are a couple of test strings from development of that system. Bear in mind these are at 200yd so cut in half for MOA. ETA: Also bear in mind I don't usually take the time to update environmental data in the Oehler system so the displayed BC's are not necessarily accurate.

Was messing with the factory 108 Match powder (similar to LVR) and 110 Atips. Didn't like the velocity spreads and didn't run it.
View attachment 8474285

15 shot string with book max charge (gas gun data) of Varget and 110 A-tip. This ran slow but was what I ended up taking to the finale.
View attachment 8474287

20 rounds of Factory 108 Match. Ran this early in the season at Cameo.
View attachment 8474289

Just curious, did you ever seat your bullets longer than 2.25-2.26" (factory) in an effort to tune or grab a little more velocity (via capacity). All assuming you had mags that would afford this. Just curious if this is worthwhile with 6 ARC?

 

[232593]

6mm ARC is pretty forgiving for barrel life anyway. I've pushed 60,000psi Varget/110 loads for 4500 rounds and pulled the barrel because I was scared, not because it stopped shooting. Have run 3500 rounds on another barrel that's still shooting well, and we have a collective barrel that has ~5000 rounds on it now (mix of factory and Varget loads) and still shooting. Our friends in the DoD have take gas gun barrels over 7000 rounds and maintained acceptable accuracy for their purposes (maybe not match shooting purposes). Pulled my gas gun PRS barrel at ~3000 rounds and gave it to a co-worker.

At any rate I'd say 4000-5000 is probably going to be pretty standard for decent PRS use.

3500 rounds? What did the gas port look like at that round count?

 

[Ledzep]

Just curious, did you ever seat your bullets longer than 2.25-2.26" (factory) in an effort to tune or grab a little more velocity (via capacity). All assuming you had mags that would afford this. Just curious if this is worthwhile with 6 ARC?

I put everything at 2.245" just to make sure it ran. You could probably go a little longer but I never messed with it.

3500 rounds? What did the gas port look like at that round count?

Dont know. Still shot well and functioned so I didn't think to look

 

[BurtG]

I've never seen a single target in any match I remember shooting that was smaller than 1moa. In every match I've shot,

????

There were half moa wide bars at 400 yards at the last match. I shot.
A couple cleans a couple 9/10s

1 moa at 100 doesn’t mean 1 moa at 500

And a 1/2 or 1/3 moa gun is going to give you a easier time.

 

[Hecouldgoalltheway]

????

There were half moa wide bars at 400 yards at the last match. I shot.
A couple cleans a couple 9/10s
View attachment 8485422View attachment 8485423


1 moa at 100 doesn’t mean 1 moa at 500

And a 1/2 or 1/3 moa gun is going to give you a easier time.

Read my statement again. I said that if you shot 1moa all day long you wouldn't miss a target. I guess you've got me on the bowling pins and some odd shaped targets though. I do remember seeing targets that were sub moa in one dimension, and then 3 or 4 moa the other way. I have seen that. 1 moa is the same at 100y as it is at 5,000y. If you shoot 1moa at every target, then 1moa is good enough. Now, that's hard to do, but my statement stands. 50%+ are 2moa or larger as you well know. I was just making the point that if you had a rifle that shot 1moa as a new shooter, your gun won't be holding you back.

 

[232593]

????

There were half moa wide bars at 400 yards at the last match. I shot.
A couple cleans a couple 9/10s
View attachment 8485422View attachment 8485423


1 moa at 100 doesn’t mean 1 moa at 500

And a 1/2 or 1/3 moa gun is going to give you an easier time.

You hit them all and was it a gas gun match?

 

[232593]

I put everything at 2.245" just to make sure it ran. You could probably go a little longer but I never messed with it.

Dont know. Still shot well and functioned so I didn't think to look

If you get around to checking I’d be interested in what you find.

 

[BurtG]

You hit them all and was it a gas gun match?

Me ? Ha hahaha


No. I am out of practice among other issues. But I did hit it 5 times. I looked it up no cleans but a fair amount of 8 and 9 out of 10.

It’s a Prs match mostly bolt guns. But there were 2 gassers. They did 5 and 3 out of 10

 

[Fatelvis]

If you don't care about barrel life go with N540 ... more temp stable than LVR and will give you more speed than Varget.

Is N540 known to be a barrel burner?

 

[tjcazes]

Is N540 known to be a barrel burner?

its an interesting rabbit hole to go down but thats most powders of the same base construction. i wanted to run n530 but they discontinued it last year. idk if 540 is hot enough...

 

[NewDog]

its an interesting rabbit hole to go down but thats most powders of the same base construction. i wanted to run n530 but they discontinued it last year. idk if 540 is hot enough...

N540 is a great powder I use it all the time. Burns much cleaner than Lever and I get good velocities. N530 is available as well but it's extremely fast burning and I would only recommend for lighter bullets 95gr and under. I'm currently in the experimental stage figuring out what I will use to replace Lever. Lever just burns too dirty and is definitely temp sensitive. Just to give you a a rough idea I can get 2800 + or - with both N540 and Lever no problem. I have a 25" McGowan barrel with +2 gas. I've shot several thousand rounds through my 20,22,and 25" barrels combined so I've tried mucho different powders over the past few years. Also tried IMR 4895 which shoots great but is a bit slower than Lever or N540. Typically 50 fps give or take for a full case but it shoots really nice.

 

[marc.south1972]

i added a next gen ec tuner brake on mine see the pictures .

 

[Jdowns0415]

27.0 grains of varget and 105 bergers/106 A Tips at 2.245 COAL seem to be working well out of my Odinworks barrel. I get just over .5 MOA 5 shot groups and have been hammering 2/3 IPSC's out to 1100 yards consistently to the point where doing it from the prone is boring.

 

[Tbd-96]

In my opinion, you can reasonably expect 3/4 MOA from a gas gun for 20 shot strings and to get much better than that the stars have to align. This is from a bench, bipod and bag with consistent fore-end loading. There are a bunch of sub-1/2 MOA 5-shot groups in what I just posted above but that isn't indicative of the capability of the system. It was a 3/4-1 MOA rifle that could have the MPOI pushed around by as much as .3-.8 mils depending on handguard loading-- which is the real weak point of the gas gun game. I have shot 3/4 MOA bolt guns in the same style matches and finished top 20 or even top 10. The MPOI movement made my gas gun finishes in the 60th-90th place range.

Is this mpoi shift present for all AR-15s or are there some handguards that are less susceptible to it. Asking before I buy this Seekins mcsr v2