AR-10 Loads

[gpr]

Do AR-10's not handle pressure as well as bolt guns? what i mean by this is, due to the bolt design and being gas operated, do they need to run at significantly lower pressure then the same chamber in a bolt gun?

I have a great load i use in my Tikka 6.5cm of 46.4gr of RL-26 and 147eld's. In the AR-10 6.5cm i have i started significantly lower at 43grs, and yet still it blows primers. Is this normal?

I'm wondering where to go as that seems like a greatly reduced load. Should I try a different powder? I was loading them with WLR or Federal 210m primers at 2.800" oal.

The ar-10 has a rifle length gas system, adjustable gas block i have turned way down as i shoot suppressed. It has a H2 buffer which i think is the regular rifle buffer, and a Tubbs flat wire spring.

Any ideas or recommendations on why I'm seeing such high pressure signs on a mild load?

 

[ChitownCopper]

Do you have a high pressure bolt?

 

[diggler1833]

Small or large primers? It can make a difference.

 

[nn8734]

Have you shot any factory ammo through it?

If so, what ammo and How does it handle the factory ammo?

 

[whatsupdoc]

Try shooting the rifle with the gas turned off. see what happens. Could be pressure is not the issue but bolt unlocking too soon.

 

[shax2lex]

Like he said, do you have a high pressure bolt?

 

[shax2lex]

Do you have a high pressure bolt?

Like he said, do you have a high pressure bolt?

 

[7mmFanBoy]

Do AR-10's not handle pressure as well as bolt guns? Yes , add more jump use lighter bullets, use harder brass

 

[ChitownCopper]

Mine shoots 178 just fine. I use what ever brass I find at the range just full size and go. Get about 5 to 6 reloads but brass is free

 

[Coyote Kev]

My AR10s don’t handle pressure. 260 Rem would blow primers on factory ammo. I’ve found you’re better off shooting medium heavy bullets like a 123 out of the 6.5. They still have an excellent BC and you can push them a little faster. You just can’t push really heavy bullets fast enough out of a gas gun to take advantage of their high BC.

 

[Captrjc]

You didn’t mention your coal. More jump may be needed.

 

[Billiam1211]

Rifles are all different. I wouldn't mix ammo from 1 rifle with another. With 175gr Matchkings, my LR308 can't handle more than 42.5 grains of Varget, 42 grains of H4895, or more than 42.6 grains of IMR 4064 without excessive pressure or popping primers.

At the moment I'm running 43 grains of Reloader 15 which is getting me 2690 fps and fantastic accuracy with 0 signs of pressure. You just need to work up a safe load for that specific rifle.

 

[gpr]

My COAL is 2.800" which is what Hornady factory ammo is set to. I don't know my jump as it is a bitch trying to measure it in this ar10. i tried several times with no good readings.

It isn't a high pressure bolt. This is a Stag Left handed AR-10, so i don't believe i can get a HP bolt. Unless you could simply install one upside down so the extractor is on the left side?????

what is the difference between a regular bolt and a high pressure one?

I had the bolt out the other day and polished up the extractor as it was leaving really rough marks on the case rim. Once i did this it helped tremendously to not jack up the brass. I then wanted ot remove the ejector, however that roll pin holding it in is so small I don't have anything to remove it. I wanted to chamfer the hole and polish the bolt face a bit to eliminate the chance of it marking up the brass.

I went back and looked at the cases i shot of factor federal ammo. it is showing ejector marks on all of the brass. some bad enough i can fill it with my fingernail. I'm starting to think something else is causing this and i need to resolve this issue before reloading. I'm thinking about a JP SCS to add weight and a stiffer spring.

I put a Tubbs flat wire spring in, and I can't remember if this is when an issue started but the gun recoils hard, to the point it is causing the charging handle latch to release. I'm wondering if my buffer is bottoming out? (btw, its real hard to shoot good when your worried you'll get smacked in the face by the charging handle)

I'm thinking of turning the adjustable gas block all the way off and see what happens and if i still get ejector marks.

BTW, i tested shooting with and with out the suppressor and i still blew out primers.

I am using larger primers. I have tried WLR and Fed210M primers. I know in AR-15's they have specific hard primers so you don't get slam fires, so they make something like this in large rifle primers that i should be using? I like the Federal 210m as they are very consistent in my other guns.

attached is a pic of the factory ammo i shot out of this gun the other day.

 

[mudpig]

There are AR-15 and AR-10 Flat wire springs from Tubbs. Are you sure you got the correct one. Sounds like the gas system isn't balanced yet. Too much gas....not enough buffer mass/spring preload.

 

[lennyo3034]

RL-26 is a slower burning powder, meaning you’re going to have higher pressures at the gas port than say H4350. This will result in faster extraction and cycling. The pressure in the chamber is probably still too high for the primer.

What barrel length and gas system length?

 

[gpr]

Yes it is the ar-10 tubbs flat wire spring.

It is a 20" barrel with rifle length gas system. I have turned the gas down with the adjustable gas block. I do have some rounds loaded up with superformance i want to shoot and see what happens.

 

[LDO416]

I'm having the same issue with my LR.308. Flattened primers and Cratering in my LR 308 and no issues in my bolt action. I use two different uppers on my LR 308. Both are Criterion M118LR chambers. On is 20 inch Rifle Length Gas System, the other is 18 Inch Mid Length Gas System. Both uppers are cycling flawlessly. Ammo being used is M118LR and Norma Match. Both with 175GR BTHP. I fire these same rounds through my Bolt Action with a 20 inch Barrel, and they have no pressure signs.

 

[Earnhardt]

9-10 oz buffer
Tubbs AR10 flat wire
Adj gas block
Hp bolt
…Fixes a lot of problems

 

[Matches Malone]

HP bolt.

 

[larryh128]

What Earnhart said. Add a 9 oz buffer to it. It's un locking too fast. I seriously doubt you will be able to run 43 grs. My upper limit using RL-17 x 130 gr was 40 grs. Basically same set up as yours but with a 9 oz buffer.

 

[phidelt208]

+1 for the HP bolt, I run 140, 143, & 142 SMK, going at 2745 ish from a 24" barrel No issues.
I'm exactly 1385 rounds on my current barrel, there are some mild cratering of the primer (large primer) and small ejector swipes on my cases.
Yes, these are high-pressure signs, but I'm not seeing any issues or excessive wear.
I'm getting 7 firings out of my brass (Hornady). With a bore scope, my barrel looks fine, normal wear for a 6.5 creed mid life, amd the bolt face has zero damage. Take it for what is.
Adjustable gas block, running this as low as possible and still 100% reliable with a filthy rifle.
Normal 308 spring, and rifle buffer.
Factory Hornady 140gr ELD Match ammo cases look the same as my handloads after firing, so I'm good with it and a whole lot of people running the same ammo in their gas guns for 3gun have no issues.

I looked at your photo it didn't look like you have much cratering of the primers. I believe Federal 210m primers are softer right.........
I wouldn't worry about the ejector swipes that can be dependent on the bolt and have little to do with pressure signs, not all the time but its not a reliable indicator in my experience, but primer crater is a good indicator.
If you're blowing primers that's clearly not good, you may just have to reduce the load if that's happening.

 

[LDO416]

9-10 oz buffer
Tubbs AR10 flat wire
Adj gas block
Hp bolt
…Fixes a lot of problems

I have done the following things. Used a Heavy buffer, 5.3 oz. Added an extra power (308) springco buffer spring. Used an adjustable gas block. Switched to HP Bolt. Added heavier bolt carrier. I have even moved to a rifle length stock with rifle buffer system. I have been able to eliminate the Case Head Swipe, but I am still getting flattened primers using factory M118LR and Federal GM. I have never seen a 10 oz carbine buffer. the heaviest I have seen is 5.6 oz.

 

[mtrmn]

I have done the following things. Used a Heavy buffer, 5.3 oz. Added an extra power (308) springco buffer spring. Used an adjustable gas block. Switched to HP Bolt. Added heavier bolt carrier. I have even moved to a rifle length stock with rifle buffer system. I have been able to eliminate the Case Head Swipe, but I am still getting flattened primers using factory M118LR and Federal GM. I have never seen a 10 oz carbine buffer. the heaviest I have seen is 5.6 oz.

Heavybuffers.com

Go there and study closely the options offered. Email them and give the specs on your gun and the symptoms. Of utmost importance is the internal depth of your buffer tube in relation to buffer length. A rifle length buffer tube must use a rifle length buffer and a rifle spring and a fixed stock if that is what you have now.

 

[samnev]

My COAL is 2.800" which is what Hornady factory ammo is set to. I don't know my jump as it is a bitch trying to measure it in this ar10. i tried several times with no good readings.

It isn't a high pressure bolt. This is a Stag Left handed AR-10, so i don't believe i can get a HP bolt. Unless you could simply install one upside down so the extractor is on the left side?????

what is the difference between a regular bolt and a high pressure one?

I had the bolt out the other day and polished up the extractor as it was leaving really rough marks on the case rim. Once i did this it helped tremendously to not jack up the brass. I then wanted ot remove the ejector, however that roll pin holding it in is so small I don't have anything to remove it. I wanted to chamfer the hole and polish the bolt face a bit to eliminate the chance of it marking up the brass.

I went back and looked at the cases i shot of factor federal ammo. it is showing ejector marks on all of the brass. some bad enough i can fill it with my fingernail. I'm starting to think something else is causing this and i need to resolve this issue before reloading. I'm thinking about a JP SCS to add weight and a stiffer spring.

I put a Tubbs flat wire spring in, and I can't remember if this is when an issue started but the gun recoils hard, to the point it is causing the charging handle latch to release. I'm wondering if my buffer is bottoming out? (btw, its real hard to shoot good when your worried you'll get smacked in the face by the charging handle)

I'm thinking of turning the adjustable gas block all the way off and see what happens and if i still get ejector marks.

BTW, i tested shooting with and with out the suppressor and i still blew out primers.

I am using larger primers. I have tried WLR and Fed210M primers. I know in AR-15's they have specific hard primers so you don't get slam fires, so they make something like this in large rifle primers that i should be using? I like the Federal 210m as they are very consistent in my other guns.

attached is a pic of the factory ammo i shot out of this gun the other day.

If you want to use the primers that prevent slam fires CCI 34's are what you want for your AR10. CCI 41's for AR15"s. I use 38 grains of iMR 4895 in all my AR 10"s. Never had primer problems and is a very accurate load for me. YMMV.

 

[LDO416]

Heavybuffers.com

Go there and study closely the options offered. Email them and give the specs on your gun and the symptoms. Of utmost importance is the internal depth of your buffer tube in relation to buffer length. A rifle length buffer tube must use a rifle length buffer and a rifle spring and a fixed stock if that is what you have now.

Great information! Thanks.

 

[bfoosh006]

IMHO, and as mentioned , RL-26 is to slow of a powder for a Large Frame AR... your gas system is going to be doing wonky things to the BCG and then the brass. The pressure curve is messing with you.
Right here..
https://www.snipershide.com/shooting/threads/6-5-creedmoor-ar-only.7023990/

And There is a decent amount of info over here...

https://www.ar15.com/forums/Precisi...OR-PRECISION-LOAD-RECIPE-THREAD/10-27/?page=1