New 6mm Advanced Rifle Cartridge

[Dino11]

How are you weighing your loads, and have you checked your scale with check weights.

Loading to Hornady spec should not have given you an over pressure load. But if your scale is off you might be unintentionally loading your rounds hot. I had a digital scale go wonky on me one time, except it was loading light thankfully. I lost 350 fps on a proven load.

 

[raptor99]

Tearing up the case head sounds like your rifle is over-gassed. Fix that first, and if you're using Lever it needs to be tuned for that, not some other powder. Forget about ejection pattern, adjust the gas so the carrier just barely locks back on the last round in a mag, then back the screw out 1/8-1/4 turn. Depending how badly your rifle is over-gassed, 1/4 turn can make a big difference, so adjust carefully.

That is how I have it set now. Mine has "Clicks" I set it to where it just locks open and then go to more clicks. I tried just one click but every once in awhile it would not lock back. But the other issue is I was working with multiple loads and that kind of sucks for adjustments so I am sure I was , in fact I know I was over gassed.

 

[raptor99]

How are you weighing your loads, and have you checked your scale with check weights.

Loading to Hornady spec should not have given you an over pressure load. But if your scale is off you might be unintentionally loading your rounds hot. I had a digital scale go wonky on me one time, except it was loading light thankfully. I lost 350 fps on a proven load.

I check my scale almost every time I set down to load so it is not a scale issue. My two biggest problems was some once fired brass from another person and then using a can which was more than likely over gassed. BUT with that being said I still have had some messed up brass loading with new Starline brass using my can set so it just locks open and loading at the top of Hornadys recommended loads......

 

[raptor99]

Guess I’ll just reach out to CLE and Craddock since this is a reloading thread mostly.

I just used the same buffer set up that was on my .223 and I have switched lowers a couple of times and have had NO feeding or any other issues. Same on the one we built for my son in law. I think personally it is a none issue don't over think it......

 

[raptor99]

Guess I’ll just reach out to CLE and Craddock since this is a reloading thread mostly.

I just used the same buffer set up that was on my .223 and I have switched lowers a couple of times and have had NO feeding or any other issues. Same on the one we built for my son in law. I think personally it is a none issue don't over think it......

 

[Constructor]

I have had some of the same issues with the Starline brass. I honestly believe that was an overpressure thing since it also tore up the face of my brass. I don't understand why though I have never exceeded the max on Hornadys load recommendations. I do see now that Hodgdons data is out and they are a gran or two lighter on some of their recommendations. I have backed down my loads to match their data and have had better luck with my brass. I have now had to start all over on my load work up. I went from having two loads with 87s and 108s the shot .5 or better to trying to find something that will shoot well and not destroy the damn brass!!! I was going to ask, my son in law has a RCBS small base die. Do you think running my brass through his SB die will take out the belt?? I have miked every piece of my brass and have kept anything that is .445 or smaller on the belt. Anything over that is in another pile. I am going to try using his die when we get together again. I hope I can save some of it. I have a special made "Pick" that I use to check for a "Parting line" starting on the inside of my brass and if I find one I know it is time to scrap it because I WILL get case separation in the next firing or two. I checked all of my ARC brass and so far it is nice and slick on the inside with no line starting. It just makes me sick because you can NOT find any brass anywhere!!!

If you still have a loaded round or 2 loaded to the same level as before, loosen and twist your gas block enough to cover the port. Shoot it and see if it comes out with the same belt. If it does it is a pressure problem, if not it is likely an over-gas problem.

 

[raptor99]

If you still have a loaded round or 2 loaded to the same level as before, loosen and twist your gas block enough to cover the port. Shoot it and see if it comes out with the same belt. If it does it is a pressure problem, if not it is likely an over-gas problem.

Couldn't I do the same thing by completely closing the adjustment on the gas block???

 

[Constructor]

Couldn't I do the same thing by completely closing the adjustment on the gas block???

Yes. I skip over stuff, didn't know you had one.

 

[raptor99]

I will do that and let you know what happens. It may be awhile we just got dumped on with snow and it is suppose to be windy this weekend. Thanks again for all the help and suggestions!! Much appreciate all the help from all of you guys!!!

 

[Mac679]

I'll start w/the disclaimer here. I own Six Sigma Arms and have Lilja produce these barrels as an exclusive offering from us. We also have Lilja cut us barrels for the 6.5mm Grendel.

The jury is still out on the 6mm ARC barrels. These just started showing up in customer's mailboxes last week and I've yet to hear any feedback. Our personal test barrels have been consistent with our 6.5mm Grendel Lilja barrels. A build done correctly will easily result in sub-MOA performance. We're routinely seeing results less than 1/2-MOA.

Of course, results do vary and barrels are, in a way, like women. Some are pretty ti... Um, never mind. Performance can and will vary. That said, if you get one that shoots poorly, I want to know about it so we can get it taken care of. With all the Lilja barrels that we've sold, I've only received negative feedback once (it was shooting about 1.5-MOA) and that turned out to be an issue with the customer's build that was easily corrected once I had it in the shop (gas tube indexing issue if I remember correctly).

Please let me know if you have any questions. I'm happy to help.
-Curt

Took a chance and picked up one of the 12.5" Lilja 6ARC barrels from Six Sigma a few weeks ago. Finally managed to get some rounds through it yesterday-2421fps for 18 shots (2 didn't pick up). No accuracy report at the moment simply because an Aimpoint micro doesn't lend itself to shooting for groups. Hornady factory 108 ammo.

 

[ormandj]

FWIW, L.E. Wilson now had a micrometer top bullet seater for the 6mm ARC (not on their website yet, but you can get it from distributors): https://www.brownells.com/reloading...sku749014787-104148-158141.aspx?sku=749014787

Keep in mind this is for arbor presses.

 

[newageroman]

What arbor presses would you suggest? I didn't know about them until a few years ago, seems like a cool idea. When the dude showed me how they work a bulb went off" I can just bring all my primed brass to the range duh.." haven't done it yet. but seems legit for load dev.
I think that and neck turning will be my nexts..

 

[lennyo3034]

Finally got mine put together.

Mega MML receivers
Bartlien 24” barrel from Craddock

Only 60 rounds of factory Hornady down so far. Accuracy has been excellent. My Young’s NM carrier did not play well with the one piece gas ring on the JP bolt. Not getting a good seal. I replaced with standard rings and it’s been flawless.

Velocity with factory Hornady 108 match is right at 2700 with SD under 10. Does that sound about right? I was expecting a little faster. Maybe the barrel will speed up a bit too.

 

[Fret]

FWIW, L.E. Wilson now had a micrometer top bullet seater for the 6mm ARC (not on their website yet, but you can get it from distributors): https://www.brownells.com/reloading...sku749014787-104148-158141.aspx?sku=749014787

Keep in mind this is for arbor presses.

They've been out for awhile now:

 

[LRBuck]

Finally got mine put together.

Mega MML receivers
Bartlien 24” barrel from Craddock

Only 60 rounds of factory Hornady down so far. Accuracy has been excellent. My Young’s NM carrier did not play well with the one piece gas ring on the JP bolt. Not getting a good seal. I replaced with standard rings and it’s been flawless.

Velocity with factory Hornady 108 match is right at 2700 with SD under 10. Does that sound about right? I was expecting a little faster. Maybe the barrel will speed up a bit too.

Sounds about right I think. From what I can recall about the velocity others who posted got out of the 108s that seems in line.
I have a 22” Rock Creek from Craddock. It is a button not cut rifle like the Bartlein. I looked back and after about 60 rounds I averaged around 2690. But my barrel definitely sped up with my hand load after I passed about 150 or so rounds down the pipe. Haven’t measured speeds in the 108s lately. Might do that tomorrow if the honey do list isn’t too long.
Paul Craddock does a great job doesn’t he!
Out of curiosity, what length gas system did you go with on your 24”?

 

[lennyo3034]

Sounds about right I think. From what I can recall about the velocity others who posted got out of the 108s that seems in line.
I have a 22” Rock Creek from Craddock. It is a button not cut rifle like the Bartlein. I looked back and after about 60 rounds I averaged around 2690. But my barrel definitely sped up with my hand load after I passed about 150 or so rounds down the pipe. Haven’t measured speeds in the 108s lately. Might do that tomorrow if the honey do list isn’t too long.
Paul Craddock does a great job doesn’t he!
Out of curiosity, what length gas system did you go with on your 24”?

Rifle +2 gas on the 24”.

I plan to shoot up enough ammo to then start loading the brass. Will start with the 105 hybrids.

I’m also tinkering with some components too. I have anEC tuner brake on way I plan to use on this rifle.

 

[SBRSarge]

Finally got mine put together.

Mega MML receivers
Bartlien 24” barrel from Craddock

Only 60 rounds of factory Hornady down so far. Accuracy has been excellent. My Young’s NM carrier did not play well with the one piece gas ring on the JP bolt. Not getting a good seal. I replaced with standard rings and it’s been flawless.

Velocity with factory Hornady 108 match is right at 2700 with SD under 10. Does that sound about right? I was expecting a little faster. Maybe the barrel will speed up a bit too.

I measured 2621fps out of my Odin 18” barrel. Velocities were recorded with about 20 rounds through it. Temp was right at 32 degrees.

 

[TripleBull]

Is now getting into the 6mm arc a bad idea given the shortage of ammo and brass, on top of the shortage of primers and powder? Was thinking to get the 6 arc, but I'm not seeing brass or ammo, or dies. Seems the newer cartridges come in even shorter supply. 6.5 prc for example, haven't had a batch of brass for a year.

I've been able to find factory ammo by driving to gun stores in small towns nearby, especially in WY. Likewise, brass has been spotty, as has powder. Good availability on bullets around Denver but primers have been the crux for me. Scored a couple thousand last month so I'm all set for a while. I'm getting parts together for three 6 ARCs at the moment. About ready assemble the fist one if the go/no-go would get here.

 

[Henryrifle]

@raptor99: I may have missed some pictures but your cases with 'belts' doesn't sound good to me. I have learned a lot from @Yondering and would defer to his knowledge when it comes to ARs. In bolt guns, however, a hard extraction and measurable expansion of the brass at that point, often called the 200 line because it is about 200 thousandths from the case head, is called a clicker because the bolt clicks open as it contacts the extraction ramp and has to be forced all the way open--different from a high pressure bolt opening. The cause is either because the sizing die wasn't set to size enough of the case OR because the chamber is cut short and there is not enough chamber to support the brass. This means that too much of the case is protruding out of the back of the chamber and the only thing holding the pressure is the brass. If this is the cause, the brass will separate and cause problems very soon. The headspace could be right and that still be the problem. Any possibility you haven't check the headspace on with your bolt/barrel combo? Have you tried a Go Gauge in it? It should close on that fine and you can start adding layers of Scotch tape to the back to determine when it won't close. Each layer of tape is about .0015 to .002" thick. You should get 2 to 3 layers of tape on before the bolt won't close. If it takes more than 6 layers of tape, your headspace is not right.

You can also take your barrel out and see how much properly sized brass is poking out of the back of the chamber. Much more difficult to see on ARs as the barrel extension is largely blocking the view.

Here is an example of this problem on a bolt gun. The Go gauge should be in much further--right at the start of the extraction groove:

There are multiple problems with this chamber but it illustrates the point of not enough case support.

I have run very high pressures with H4895, not on purpose, and while I did ruin the primer pockets, there were no extraction issues or expanded cases in the area you are having issues with.

Hope that helps some...

Henryrifle

 

[Henryrifle]

A lot has been written since I last took a look here. I got a chance to shot my 6mm ARC today for fun and was happy to see that my 29 grain load of CFE 223 behind a 108 ELD is still shooting well. It shot a .62 at 100 yards with bipod and squeeze bag. I had about 42 left over from deer season:

These shot at 2643 FPS today in 67 degree weather. The last time I shot them back in October, it was 75 degrees and they shot at 2662 FPS. Maybe the velocity change is to be expected.

I also had several leftover 28.3 CFE 223 loads. They shot at an acceptable .83-ish average at 2564 FPS. Both produced SDs in the 8.0 range.

Here are the 28.3s:

As always, a fun day with the 6mm ARC.

Henryrifle

 

[67rschev]

I've been following this thread from the beginning, and the great information thanks all for posting. I have a few questions for you all after shaking down my ARC build yesterday, I'm not a gas gun guy.

I stumbled across an un-fired Odin 18 inch with bolt combo locally for a bargain, and fortunately my LGS had 10 boxes of ELD 108s on the shelf AND at pre-panic prices to get me started. The gas system is an XL plus two. While I understand this will help with brass life, bolt longevity, and felt recoil, i'm going to have to make some buffer system modifications to get this to run. Shot 40 rounds yesterday of the ELDMs, and tried tuning with what I had with me. Started with a 4 oz buffer and quickly opened up the gas block to WO and still no lock back. Changed to a 3 oz and had about 50% - 75% bolt hold open function. What reduced spring are we using? Any issues with reduced springs on the load up, as I plan on using bushing dies and really do not want to go to a small base dies if I don't have to. This morning I also ordered the KAK light buffer kit with 1.7, 2.2, 2.6 buffers to experiment with. I have a low mass carrier, I could swap over unknown if any issues with the 6.5 bolt and low mass carrier ?

Side note, accuracy is looking to be very good. First 40 rounds shown here. 5 rounds to zero at 100. five groups of 5, and one group of 10 rapid fire. Getting some Leverevolution today, as well as some die bushings. Now the quest starts to find some projectiles Ugggg

 

[Yondering]

What reduced spring are we using? Any issues with reduced springs on the load up, as I plan on using bushing dies and really do not want to go to a small base dies if I don't have to. This morning I also ordered the KAK light buffer kit with 1.7, 2.2, 2.6 buffers to experiment with. I have a low mass carrier, I could swap over unknown if any issues with the 6.5 bolt and low mass carrier ?

Unfortunately you’ll be stuck with something way outside normal gas gun setup to get Odin’s stupid +2 gas system to work right on that 18” barrel.

I suggest using your low mass carrier (no issues with the Grendel bolt there), then trying the lighter buffer weights, then going to a lighter spring as a last resort.

You shouldn’t need a small base die as long as you have your die set up correctly for .002”-.004” shoulder bump.

 

[alamo5000]

I started another thread on this but I figured I would post it here also. Mighty Armory 6ARC die is now available. Went live yesterday.

Mighty Armory GOLD MATCH 6mm ARC Sizing Decapping Die

6mm Sizing Decapping Die for precision reloading. Get consistent and accurate results with these high-quality reloading dies. Improve your shooting performance today!

www.mightyarmory.com

 

[Henryrifle]

@67rschev: That is a good beginning for your new rifle and nice shooting!--Good luck with it.

@Yondering & @67rschev - any possibility the gas block is not correctly aligned with he gas port? In my relatively limited experience, I have seen this issue several times.

Henryrifle

 

[SBRSarge]

Palmetto State Armory has 6mm ARC Black in stock for 30 bucks/box.

https://palmettostatearmory.com/hornady-black-105-gr-bthp-match-6mm-arc-ammunition-20-rounds-81604.html

 

[david walter]

Not any more....

Palmetto State Armory has 6mm ARC Black in stock for 30 bucks/box.

https://palmettostatearmory.com/hornady-black-105-gr-bthp-match-6mm-arc-ammunition-20-rounds-81604.html

 

[67rschev]

Unfortunately you’ll be stuck with something way outside normal gas gun setup to get Odin’s stupid +2 gas system to work right on that 18” barrel.

I suggest using your low mass carrier (no issues with the Grendel bolt there), then trying the lighter buffer weights, then going to a lighter spring as a last resort.

You shouldn’t need a small base die as long as you have your die set up correctly for .002”-.004” shoulder bump.

Thank you for the guidance. This is my first gas gun that has not been plug, play, go and rip. Will be a fun use of time, to see how accurate the 'cheap' barrel will stack them. Good news is found some 105 Hybreds in town to tinker with this afternoon

@67rschev: That is a good beginning for your new rifle and nice shooting!--Good luck with it.

@Yondering & @67rschev - any possibility the gas block is not correctly aligned with he gas port? In my relatively limited experience, I have seen this issue several times.

Henryrifle

The Oden gas block has alignment markings for the port on both the barrel and the block. I also used a light shmear of blue when installing the block. Been down that road of a leaky gas system a while ago, but I will double check this one again. I think the XL system with short dwell time is the cause in this instance, but I'll be using a dedicated lower, so no worries and hopefully have the benefit of longer lasting brass maybe.

 

[Yondering]

@Yondering & @67rschev - any possibility the gas block is not correctly aligned with he gas port? In my relatively limited experience, I have seen this issue several times.

Henryrifle

Other people (here and other forums) have complained of the same issues with Odin's combination of +2 rifle gas on 18" barrels. That's a combination that never should have been sold, and IMO demonstrates a lack of good product testing and of even researching what's worked before since variants of this cartridge have been proven out for over 10 years now.

 

[SWFShooter]

Other people (here and other forums) have complained of the same issues with Odin's combination of +2 rifle gas on 18" barrels. That's a combination that never should have been sold, and IMO demonstrates a lack of good product testing and of even researching what's worked before since variants of this cartridge have been proven out for over 10 years now.

Pretty much specifically a suppressor setup.

 

[Dino11]

I used a Wolff 10% reduced power action spring in my 18" Odin barreled rifle, But my rifle has a rifle length buffer system on it and they were the only game in town for reduced power springs for rifle length.. They can be a little hard to locate, not many folks use reduced power springs.

It is one of the softest shooting AR's I have ever shot and I have shot a lot of them. So the concept is really not so stupid when you factor in the benifits of it once you over come the issues of getting it to run. Just the benifit of increased dwell time is easier on both brass and the bolt, as well as some other benefits that are good for another posted thread.

 

[raptor99]

@raptor99: I may have missed some pictures but your cases with 'belts' doesn't sound good to me. I have learned a lot from @Yondering and would defer to his knowledge when it comes to ARs. In bolt guns, however, a hard extraction and measurable expansion of the brass at that point, often called the 200 line because it is about 200 thousandths from the case head, is called a clicker because the bolt clicks open as it contacts the extraction ramp and has to be forced all the way open--different from a high pressure bolt opening. The cause is either because the sizing die wasn't set to size enough of the case OR because the chamber is cut short and there is not enough chamber to support the brass. This means that too much of the case is protruding out of the back of the chamber and the only thing holding the pressure is the brass. If this is the cause, the brass will separate and cause problems very soon. The headspace could be right and that still be the problem. Any possibility you haven't check the headspace on with your bolt/barrel combo? Have you tried a Go Gauge in it? It should close on that fine and you can start adding layers of Scotch tape to the back to determine when it won't close. Each layer of tape is about .0015 to .002" thick. You should get 2 to 3 layers of tape on before the bolt won't close. If it takes more than 6 layers of tape, your headspace is not right.

You can also take your barrel out and see how much properly sized brass is poking out of the back of the chamber. Much more difficult to see on ARs as the barrel extension is largely blocking the view.

Here is an example of this problem on a bolt gun. The Go gauge should be in much further--right at the start of the extraction groove:
View attachment 7587796
There are multiple problems with this chamber but it illustrates the point of not enough case support.

I have run very high pressures with H4895, not on purpose, and while I did ruin the primer pockets, there were no extraction issues or expanded cases in the area you are having issues with.

Hope that helps some...

Henryrifle

Thank you for the reply. I don't have a go-no go gauge or know of anyone who has one. I know that part of my issue is excess pressure for a combo of using a can and going by Hornady load data. I was loading at the top of their recommended data and today I got a copy of Hodgdon's reloading data. According to "Their" data I am over max recommended loading by up to a grain+ using Hornady's data. I had a couple of loads with Varget that were .4 to .5 groups with both 87VMAX and 108ELDs. But if you have read this you know the issues that I have been having. I was using 29.5grs of Varget with the 87s and Hodgdon says the max should be 28.1grs plus you add a can and you have pressure. I was at 27grs of Varget with the 108s and Hodgdon says 25.8grs is max!! I loaded some loads last night that would be a grain to 1.5grs lighter with the 87s and 108s. I used Varget for the 87s and LVR for the 108s. The 108s were just fine but the Varget loads still showed just a trace of the belt but nothing like before. However when sizing the case I did get a small belt again. SOoo... Varget is out. I am going to start over with LVR and CFE to see if I can get some of my accuracy back with one of these powders and not get the famous "Grendel" belt. I actually cut a case in two and looked at the inside of it. There were no signs of any case head separations starting. As a side note I don't think it is a head space Issue since I don't get it with factory loads. Thanks again Henry and to all of the others on here for helping with my issue!!!

 

[Yondering]

Thank you for the reply. I don't have a go-no go gauge or know of anyone who has one. I know that part of my issue is excess pressure for a combo of using a can and going by Hornady load data. I was loading at the top of their recommended data and today I got a copy of Hodgdon's reloading data. According to "Their" data I am over max recommended loading by up to a grain+ using Hornady's data. I had a couple of loads with Varget that were .4 to .5 groups with both 87VMAX and 108ELDs. But if you have read this you know the issues that I have been having. I was using 29.5grs of Varget with the 87s and Hodgdon says the max should be 28.1grs plus you add a can and you have pressure. I was at 27grs of Varget with the 108s and Hodgdon says 25.8grs is max!! I loaded some loads last night that would be a grain to 1.5grs lighter with the 87s and 108s. I used Varget for the 87s and LVR for the 108s. The 108s were just fine but the Varget loads still showed just a trace of the belt but nothing like before. However when sizing the case I did get a small belt again. SOoo... Varget is out. I am going to start over with LVR and CFE to see if I can get some of my accuracy back with one of these powders and not get the famous "Grendel" belt. I actually cut a case in two and looked at the inside of it. There were no signs of any case head separations starting. As a side note I don't think it is a head space Issue since I don't get it with factory loads. Thanks again Henry and to all of the others on here for helping with my issue!!!

Adding a suppressor does NOT raise pressure. You keep talking like it does.

Like I said, you are not seeing pressure signs, you're seeing early extraction signs. That early extraction is caused by adding the suppressor. NOT the same thing as increased pressure.

 

[Henryrifle]

@raptor99: Glad to hear that you are getting it sorted out. I don't have deep knowledge of the AR platform like several others on this board do and I don't want to mislead you or anyone else.

I did look through my data and see that I was using 27 grains of Varget and even 27.2 grains at times. Out of my 21.75" barrel that was giving me 2626 FPS in 88 degree weather. I run my rifle suppressed as well 100% of the time. A quick check of QuickLOAD indicates that is about 8% over pressure at approximately 56,148 PSI.

CFE and Lever are both great and getting either in the current situation would be awesome. If I had to pick one, it'd be Lever. I don't really need the extra velocity it provides but will take it.

I will just say again that the only problem I have caused myself when going over pressure with my 6mm ARC is unusably expanded primer pockets. Those cases resized fine with no visible belt.

I do hope you get to the bottom of this condition soon because I really want to know the cause!

Henryrifle

 

[CIB2007]

I know it’s not the reloading section. Hodgdon has leverevolution in stock in 1lb. I had to reload the page a few times until I was able to get the order in.

Hodgdon LEVERevolution®

Hodgdon® Powder Company and Hornady® have teamed together to answer the reloading question; "Can I buy the powder used in Hornady LEVERevolution factory ammunition?" This is the same spherical propellant used in Hornady's innovative and award-winning, high-performance factory ammunition. This...

shop.hodgdon.com

 

[LRBuck]

I know it’s not the reloading section. Hodgdon has leverevolution in stock in 1lb. I had to reload the page a few times until I was able to get the order in.

Hodgdon LEVERevolution®

Hodgdon® Powder Company and Hornady® have teamed together to answer the reloading question; "Can I buy the powder used in Hornady LEVERevolution factory ammunition?" This is the same spherical propellant used in Hornady's innovative and award-winning, high-performance factory ammunition. This...

shop.hodgdon.com

Gone now.
Edit:
Don’t know what is going on with their website, but someone was kind enough to message me and let me know they were still able to order. So I went back and SUCCESSFULLY ordered. Hope I didn’t mess anyone up. Keep trying.

 

[Ironman675]

thank you sir for the heads up, just got 4#

 

[raptor99]

Adding a suppressor does NOT raise pressure. You keep talking like it does.

Like I said, you are not seeing pressure signs, you're seeing early extraction signs. That early extraction is caused by adding the suppressor. NOT the same thing as increased pressure.

If it is not increasing the pressure then why am I getting the belt when using the can and I don't get it when I don't use it?? What is causing it to want to "Unlock" to early if it isn't excess pressure???

 

[Yondering]

If it is not increasing the pressure then why am I getting the belt when using the can and I don't get it when I don't use it?? What is causing it to want to "Unlock" to early if it isn't excess pressure???

Because the suppressor increases the back pressure into the gas system, making the bolt unlock faster. That's a totally different thing than raising peak pressure, which happens while the bullet is still in the barrel and drops off before it ever makes it to the suppressor. There's no way for the suppressor to affect peak pressure when the bullet is still in the barrel.

If you blocked off the gas system, you'd see no difference in the brass between suppressed and unsuppressed. The effect of suppressors on gas systems is a known entity that most who shoot suppressed look for ways to deal with, and is the entire reason for things like the Bootleg and Gemtech switchable carriers.

 

[raptor99]

Because the suppressor increases the back pressure into the gas system, making the bolt unlock faster. That's a totally different thing than raising peak pressure, which happens while the bullet is still in the barrel and drops off before it ever makes it to the suppressor. There's no way for the suppressor to affect peak pressure when the bullet is still in the barrel.

If you blocked off the gas system, you'd see no difference in the brass between suppressed and unsuppressed. The effect of suppressors on gas systems is a known entity that most who shoot suppressed look for ways to deal with, and is the entire reason for things like the Bootleg and Gemtech switchable carriers.

Thanks Yonderling!! I have an adjustable gas block that is set as low as it will go and still function the rifle. I don't remember if it was you or someone else who told me that I needed to set it so that it just locked the bolt back and not worry about where the brass was landing. This along with dropping my load did stop the "Brass Tearing" that I was experiencing. However when I dropped the Varget load down a full grain it still put a slight belt on the case. NOT as bad as it was doing but you could still see it and then when I resized the case it was visible. Not so with the LVR loads. I have loaded some loads with both CFE and LVR and when the wind drops below 30mph I will slip out and try them and see what happens. I just hope I can find something that will shoot as well as the Varget load did......Oh by the way what is the "Bootleg" and the Switchable carriers???? Thanks again for all the help. It is MUCH appreciated!!!

 

[tomcatfan]

Here is something to lighten the mood...
Sold all my 223 dies, have a bunch of brass I need to jettison if anybody needs any.
Will have some load data/dev over there as well.

223 Rem

223 Remington brass for the AR-15

brassbucket.net

View attachment 7589950

Not sure what the mood is exactly, but this is a good way to get the ban hammer.

 

[Yondering]

Thanks Yonderling!! I have an adjustable gas block that is set as low as it will go and still function the rifle. I don't remember if it was you or someone else who told me that I needed to set it so that it just locked the bolt back and not worry about where the brass was landing. This along with dropping my load did stop the "Brass Tearing" that I was experiencing. However when I dropped the Varget load down a full grain it still put a slight belt on the case. NOT as bad as it was doing but you could still see it and then when I resized the case it was visible. Not so with the LVR loads. I have loaded some loads with both CFE and LVR and when the wind drops below 30mph I will slip out and try them and see what happens. I just hope I can find something that will shoot as well as the Varget load did......Oh by the way what is the "Bootleg" and the Switchable carriers???? Thanks again for all the help. It is MUCH appreciated!!!

Bootleg carrier: https://bootleginc.com/product/full-auto-adjustable-carrier/
The Gemtech unit is/was similar but had to be removed from the rifle for adjustment and only had 2 positions. Both of these exist as a way to switch your AR gas system between suppressed and unsuppressed function.

Use it with the adjustable gas block you already have; your gas block sets the tuning correctly unsuppressed, and then the Bootleg carrier adjustment compensates for the additional gas system pressure when shooting suppressed. Bootleg says you can use this instead of an adjustable gas block, but in my experience that doesn't work as well with rifles that are already overgassed without a suppressor, as most AR15s are.

I keep a little flat head screwdriver I made attached to the Magpul grip cap in my rifle for adjusting the bolt carrier when I install the suppressor.
I really like that you can look at it and tell where the adjustment is set, unlike most gas blocks. (It's set to position 2 in this pic.)

Here's the newer version; slightly different machining cuts on the carrier but otherwise still the same:

 

[raptor99]

Thanks again!! It looks like a neat set up and is not all that bad in price!! I was expecting it to cost a lot more.....

 

[Yondering]

Thanks again!! It looks like a neat set up and is not all that bad in price!! I was expecting it to cost a lot more.....

Yeah they are pretty reasonably priced for what they are, especially considering cheap bcg are going for ~$125+ right now. (FWIW Bootleg does sell a standard bcg for $130 but I've never tried it.) These adjustable carriers have some other nice features too; the wear surfaces have cleaning grooves in them, and just going by the examples I have, the cam slot profile seems a little different and more optimized for suppressed use with delayed unlocking.

IMO these are currently the best way to switch between suppressed and unsuppressed and keep the rifle tuned correctly in both conditions. I can't afford to use them in all my rifles, but use them in the worst offenders (at the moment my 12.5" 6.5 Grendel and 6mm Grendel barrels.)

 

[brazz04]

You guys all know too damn much about AR's. Reading and learning. Just bought a 12" ARC barrel off the grendel/ARC forum and am ready to put some of this info to use.

 

[raptor99]

You guys all know too damn much about AR's. Reading and learning. Just bought a 12" ARC barrel off the grendel/ARC forum and am ready to put some of this info to use.

Welcome and you came to the right place!!! Lot of knowledge in these pages. Just take the time to read them!!!

 

[Gtscotty]

I got my 21" Odin Works set up and have made a few range trips with it, the first to burn up some factory 108gr for brass, and then a few load development attempts.

Out of my 21" barrel, 108gr factory loads chrono'd at an average of 2,663 fps.

First loads were some 85gr Sierra GKs I had laying around and 105gr Barnes, both over LVR.

Not terrible, except when I loaded up some varying oals for 85gr with 31gr LVR, and 105gr with 29.2 gr LVR and went back, things fell apart for no apparent reason. Only real difference was that the second trip was about 30 deg cooler than the first. I almost always use temp insensitive powders, so my experience with sensitive ball powders is very limited, but I wouldn't think there's any way a 30 deg temp difference could change velocities enough to throw you out of a node? I also wound up having to turn up the gas on the second trip a few clicks. Admittedly I set the GB up so the rifle will run suppressed but not otherwise, still, no failures the first trip, but it started feeling sluggish and failing to strip the next round (only with the 105s, 85s cycled fine) on the second cooler trip. Alternatively, I may have just been shooting poorly the second trip. More work to be done, but ~ 2,950 seems pretty healthy for 85 gr though!

 

[raptor99]

85s at that velocity would make one hell of a good coyote load!!

 

[67rschev]

@Gtscotty Hoping with careful loading, my Odin will preform as well as yours is showing

Side note, tossed the 40 pieces of once fire Hornady 108 M from the initial sight in and function testing in the Thumbler. A bit of a surprise as around a third of the brass exhibited that slight 'Grendel Belt' discussed, measuring in at just under .001. Suppose I had forgotten what suspect brass they make in Nebraska, learned that about ten years ago fooling with Hornady cases in another project. Thinking I should start looking for some Lapua 220 to convert, and eagerly awaiting other brass manufactures to jump on board with the caliber.

 

[Yondering]

@Gtscotty Hoping with careful loading, my Odin will preform as well as yours is showing

Side note, tossed the 40 pieces of once fire Hornady 108 M from the initial sight in and function testing in the Thumbler. A bit of a surprise as around a third of the brass exhibited that slight 'Grendel Belt' discussed, measuring in at just under .001. Suppose I had forgotten what suspect brass they make in Nebraska, learned that about ten years ago fooling with Hornady cases in another project. Thinking I should start looking for some Lapua 220 to convert, and eagerly awaiting other brass manufactures to jump on board with the caliber.


View attachment 7592175View attachment 7592176

That "belt" starts pretty far from the case head; looks like your chamber's feed ramp was cut/beveled too deep (that's a good example of what LedZep was talking about earlier), or the rifle is extracting prematurely due to being severely overgassed.

Also, you'd want to form brass from Grendel cases (Lapua or otherwise) rather than 220 Russian, unless you want to waste more components in fireforming.

 

[Gtscotty]

@Gtscotty Hoping with careful loading, my Odin will preform as well as yours is showing

Side note, tossed the 40 pieces of once fire Hornady 108 M from the initial sight in and function testing in the Thumbler. A bit of a surprise as around a third of the brass exhibited that slight 'Grendel Belt' discussed, measuring in at just under .001. Suppose I had forgotten what suspect brass they make in Nebraska, learned that about ten years ago fooling with Hornady cases in another project. Thinking I should start looking for some Lapua 220 to convert, and eagerly awaiting other brass manufactures to jump on board with the caliber.


View attachment 7592175View attachment 7592176

I had the exact same ring on about a third of my first firing of factory 108s as well. I'm using the RCBS SB dies (gotta use what you can find) and they ironed out the line pretty well. I was thinking it must be a sloppy chamber or long headspace. I can still see a line on about a third of the brass after my third firing, but it's pretty faint, and the balance of my cases don't have it, which seems pretty weird if it's a sloppy chamber. I think I'm pushing the shoulder back about 3 thou, maybe the factory loaded cases were under sized? I have some left, I'll have to check some time when I think about it.