6mm ARC Help

[bryant00]

Build:
Aero Enhanced upper and handguard 15"
Shaw 18" barrel .750 rifle length gas
SA adjustable gas block
Aero gas tube
ToolCraft 6.5 general type 2 DLC BCG and bolt
Aero lower
Stoner parts kit
LaRue MBT
H1 buffer
JP polished buffer spring
Sandman S suppressor

All shooting done suppressed.

I'm well sub MOA with Hornady Black 105. Ejection tuned and running right at about 3 o'clock.

Multiple hand loads are just fine and several under .5 MOA

Hand Loads are:
Hornady fired brass. 105 Match Burners. Lerver at 29.4. Ogive is same as Hornady Black at 1.689. This shoots almost exactly like Hornady Black.

Starline 6.5 Grendel brass full length sized. 105 Match Burners. Lerver at 29.6. Ogive is same as Hornady Black at 1.689. This shoots almost exactly like Hornady Black.

Hornady fired brass. 105 Hornady bthp. CFE at 28.6. Ogive is same as Hornady Black at 1.689. This shoots almost exactly like Hornady Black.

With all those working great, loaded up some new Starline 6 ARC, ( NOT Grendel) with the 107 SMKs. Lever with loads from 29.4-30.2 at .2 increments. Same ogive as the other loads.

Here's the problem:
With that last load of 107/Starline/Lever, I'm having massive extraction issues. Dialed gas block up another 15 clicks and then to almost closed and no change. Rounds were getting ejected from 2 o'clock to just barely falling out of the gun.

I could switch back to the other loads and after dialing back the gas to the normal setting everything was fine with those other rounds.

My buddy was dialing in his Odin setup and had ZERO issues with that same ammo load, nor did he have issues with the other loads.

WTF is going on here with those 107/Starline/Lever loads?!?!? Me and my buddies have no clue. Any thoughts would be helpful.

Thanks for viewing.

 

[Hardholder439]

Have you measured velocity with a labradar or chrono? How do the various loads compare in velocity? It may or may not provide the clue you are looking for.

 

[bryant00]

Have you measured velocity with a labradar or chrono? How do the various loads compare in velocity? It may or may not provide the clue you are looking for.

Good idea. I've not yet. I will say that POI is almost the exact as the "working normal" rounds at 100 yards. It's a measurement I've not done but I would imagine if the velocity was drastically different I would see an impact difference on the paper.

 

[357Max]

Odin barrel is +2 rifle gas vs your std rifle. 30.2 is 1/2gr over max for Lever & Lever makes a ton of port pressure. Probably a timing issue with your shorter gas system trying to unlock while the case is still expanded.

 

[bryant00]

Odin barrel is +2 rifle gas vs your std rifle. 30.2 is 1/2gr over max for Lever & Lever makes a ton of port pressure. Probably a timing issue with your shorter gas system trying to unlock while the case is still expanded.

The loads worked up to 30.2. Starting was 29.4. Cycling issues were at Every powder load, 29.4, 29.6, 29.8, 30 and 30.2.

We realized that 30.2 is MAX for Both out guns because of primer flattening and some burrs on the brass.

Great observations and input! I'd love to hear more thoughts.

 

[DHDeal]

Out of curiosity, how does the new Starline ARC brass feed? Have you checked to see if it drops in with resistance? Try focusing on just the Starline ARC brass with a clean chamber. I also would run the new brass into your sizer as it may be a little snug in your chamber before loading the cases (if you weren't doing that to start with). Can't hurt at least.

I know from my shooting partners ARC (Odin 21" barrel) it showed pressure signs at a lower powder charge then we expected but always shot extremely well. My experience is with multiple 6.5 Grendels and thousands of rounds through them. To me, even though they are more or less the same case, they are 2 very different cats. We are waiting on the Starline ARC brass to come back in stock to try it. He has only used Lapua 6.5 Grendel reformed and it has been a picky beast.

 

[db2000]

I was getting moderate pressure signs with plunger circle stamps on the head with 30.0 and up LVR and Sierra 107’s. I have an 18” SS Shaw and Rifle length SA adjustable and geissele super braided w/ H3 buffer carbine length. No extraction issues. SiCo Omega can.

 

[alamo5000]

I had a barrel custom made from McGowan with a shorter gas system. I think I did just regular rifle length.

In 6 ARC it's very easy to get over gassed just by nature of the cartridge. There is a reason why some manufacturers are doing +1 and +2 gas lengths.

I wound up using an H3 buffer in mine.

 

[bryant00]

I've FOUND THE ISSUE!!

NOTE: I'm going to mention some vendor names here. PLEASE do not take this as "These vendors/manufacturers suck and make terrible products." I have multiple experiences with this vendor and this manufacturer and their reputation as a vendor and manufacturer have been stellar!

Went out on Saturday. Still having issues with the new SA gas block as the replacement for the Aero AGB because I thought the Aero AGB might have contributed to the issue. Hornady brass almost 100% flawless ejection right at about 2:45/3. Starline brass, still problems. Here's what I did:

1. Swapped BCG's with buddy's Odin.
   1. Ran PERFECT, just like his
2. Kept the ToolCraft BCG but switched the Odin bolt
   1. Ran PERFECT
3. Swapped out the ToolCraft extractor spring with brand new one from the range shop
   1. Ran BETTER, but NOT perfect.

I reached out to Arm or Ally, the vendor of the ToolCraft BCG, and explained to them the issue. This was very late Saturday evening. Monday morning by 8am I had an email from Arm or Ally with their response that included ToolCraft. ToolCraft said they were happy to exchange the bolt and sent a pre-paid shipping label for the return/exchange.

I'm very grateful for vendors and manufacturers like them. I will continue to throw business their way. I understand that we're not all perfect and that mistakes can happen. The customer service of both of these companies is fantastic and the warranty from ToolCraft is amazing. I'll keep this thread up to date when I have a new bolt/bcg to test out.

Thanks for all the great ideas and I'm hoping it's just a small tolerance issue that we can all learn from.

 

[DHDeal]

Interesting. I'll assume this was using the previously problematic Starline 6ARC brass.

I've been pretty lucky with bolts working without issue but still keep spares on hand. Hey, at least it's a cheap hobby were in....

 

[LRBuck]

I've FOUND THE ISSUE!!

NOTE: I'm going to mention some vendor names here. PLEASE do not take this as "These vendors/manufacturers suck and make terrible products." I have multiple experiences with this vendor and this manufacturer and their reputation as a vendor and manufacturer have been stellar!

Went out on Saturday. Still having issues with the new SA gas block as the replacement for the Aero AGB because I thought the Aero AGB might have contributed to the issue. Hornady brass almost 100% flawless ejection right at about 2:45/3. Starline brass, still problems. Here's what I did:

1. Swapped BCG's with buddy's Odin.
   1. Ran PERFECT, just like his
2. Kept the ToolCraft BCG but switched the Odin bolt
   1. Ran PERFECT
3. Swapped out the ToolCraft extractor spring with brand new one from the range shop
   1. Ran BETTER, but NOT perfect.

I reached out to Arm or Ally, the vendor of the ToolCraft BCG, and explained to them the issue. This was very late Saturday evening. Monday morning by 8am I had an email from Arm or Ally with their response that included ToolCraft. ToolCraft said they were happy to exchange the bolt and sent a pre-paid shipping label for the return/exchange.

I'm very grateful for vendors and manufacturers like them. I will continue to throw business their way. I understand that we're not all perfect and that mistakes can happen. The customer service of both of these companies is fantastic and the warranty from ToolCraft is amazing. I'll keep this thread up to date when I have a new bolt/bcg to test out.

Thanks for all the great ideas and I'm hoping it's just a small tolerance issue that we can all learn from.

I’ve always had good experience with Arm or Ally as well. Few issues but quickly resolved when I or my son did. Glad to hear Toolcraft is responsive as well. Companies that do right deserve a shout out. Thanks for sharing.

 

[12Bravo20]

Glad to hear you got the issues figured out.

I am running an Odin Works 18" with +2 rifle gas along with an Odin Works bolt.I haven't had any issues with factory ammo. I haven't tried any reloads yet.

 

[bryant00]

Back In BUSINESS!!

All brass is ejecting perfectly now right about about the 330. And YEETING it out of there for the most part and putting a little bit of a dent in the neck because it's slamming the deflector. I can certainly tune the gas a little bit more but the issue of the bolt has been resolved.

I can't thank Arm or Ally and ToolCraft for coming to such a quick resolution. I'll be shopping there more and more because of their customer service. Thanks for all the tips and ideas guys. Have a great week.

 

[bfoosh006]

Good to hear, I would apply a adhesive backed fuzzy side piece of velcro on your deflector. ( Cut to fit )

 

[Bantam1]

I used one of those foam ones that were made for the deflector to stop the damage. I can't remember who makes them. I think it comes in a kit with 3 of them? Anyways it stopped the flat spots in the neck and the brass drops in a nice little pile about 12" away to my 3:00.

 

[12Bravo20]

Back In BUSINESS!!

All brass is ejecting perfectly now right about about the 330. And YEETING it out of there for the most part and putting a little bit of a dent in the neck because it's slamming the deflector. I can certainly tune the gas a little bit more but the issue of the bolt has been resolved.

I can't thank Arm or Ally and ToolCraft for coming to such a quick resolution. I'll be shopping there more and more because of their customer service. Thanks for all the tips and ideas guys. Have a great week.

Glad to hear you got everything fixed and also good to hear about the excellent customer service from both companies.

While I have never had to contact Arm or Ally for any issues, They have always been quick to answer questions for me.

 

[LRBuck]

I used one of those foam ones that were made for the deflector to stop the damage. I can't remember who makes them. I think it comes in a kit with 3 of them? Anyways it stopped the flat spots in the neck and the brass drops in a nice little pile about 12" away to my 3:00.

I have never seen/tried a kit, but I use some thin black foam strip with one sided tape. Works well. I replace it every few months or so, but I have 6 ft strip and use less than an inch at a time.

 

[Bantam1]

I found it. Had to dig though emails to find the order. I got it through Amazon on sale.

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