Broke another bolt.... your thoughts??

[Cajuntransplant]

Cajun,

Two more points...Unless your friend has drilled holes in his barrel it is physically impossible for your shorter 18" barrel to be faster than his 20", with the same ammo. At 18/20" we're talking about 50fps difference (roughly 25fps/inch). If your shorter gun is faster with the same ammo something is wrong with the measuring equipment or regime. You did say it's similar so it's not the same batch loaded by the same person. I am thinking for him to be slower than you his ammunition is milder and definitely not 'almost similar'. A grain or two makes a big difference when you are at the limit of the equipment. BTW, the loads I quoted above are not mild loads, they are on the edge of what I would call maximum.

Suppressors will never lower the velocity of your gun. Typically they add a few fps more due a phenomenon called 'freebore boost'. Suppressors are a containment vessel which allows expansion and cooling but still contains it. Even though the bullet is no longer sealed against the barrel walls there is still a bit more pressure behind the bullet as it passes through the suppressor than if it was the open air. This adds about 5fps more.

Lol. I know. But it did. Same powder, bullet, charge weight, primers, everything. My 18” satern barrel ran at 2600 avg and his 20” proof ran at 2585-ish. Today (break in must be done) 2614. Same chronograph setup too. Yeah I typed wrong. Checked my notes. My speed went up from 2515 to 2522 once I added the suppressor. Is the quickload data published through here on the forum considered max load? Cause my accuracy nodes are in the higher velocity range and that’s what is giving me my problems now. Maybe I just completely skipped over the lower node?

[Klem]

I find QL invaluable but it's only a computer model. The German engineers lean on the conservative side, probably to avoid the hassle of potential litigation. It's not a bad program to use with AR loading given the AR receiver is so unforgiving to over-pressure. I use it in conjunction with bullet and powder manufacturer load pages. Any load advice from other people including this forum is also considered but there's not one source that I treat as definitive. QL lists SAAMI or CIP limits which seem to be slightly less than the recommended loads on this forum. I am happy using QL limits knowing that means I have a little safety fudge factor on top. The target and the animal is not going to notice a difference of 100fps. Sure, some pressure/velocities are more accurate than others so it's all about setting a limit and finding what's the most accurate load closest to that.

[Sticks]

I agree that you are on the too hot side.

I have a 18" Bartlien that runs 2475 on factory ELD that is near impossible to match safely.

24" Lilja that matches your speeds with factory.

4 Howa 20" that hang in the low 2500s.

Your loads are too hot.

[Joseph5]

His loads may certainly be to hot but if it is the same lug breaking of each time that could point to an unequal distribution of strain which should also be addressed. If he lowers pressures and one lug is taking more strain than the rest he will still have problems, it will just take longer between events.

[Cajuntransplant]

I can't find my old load data book with the numbers going back from when I first got it and all the load dev I did on the rifle. Probably lost it in the move.. which sucks. I'm going to pickup a couple boxes of factory ammo and see where I am at. Some 123eldm and the 123sst factory loads. I'll see what that ammo runs at for speed and what the brass looks like and go from there. Thanks to everyone for all the replies. I'll let you know what results I end up with and will try to find my old book with all the original load info I had on the rifle.

[Redraider]

Cajun,
Do your loads fall in and out of chamber with gravity only? If you have to apply slight finger pressure to "seat" your rounds, will they fall out without help?

Redraider

[Cajuntransplant]

Cajun,
Do your loads fall in and out of chamber with gravity only? If you have to apply slight finger pressure to "seat" your rounds, will they fall out without help?

Redraider

I can check when I get home to see. Cleaned everything up real good last night and put her back in the safe.

[muvef]

Your loads are hot. Both your loads are 100fps hotter than mine.

Too hot is the first things that stands out. It might also be that the bolt lugs are not all resting square against the barrel extensions lugs. That would mean only one lug is taking all the pressure. If this, then you need a new barrel.

I would drop your loads by 100fps and see how that goes before spending any money on the rest of the gun.

These are my thoughts as well.

If you have a new bolt watch for a wear pattern on back of the lugs. The lugs should show equal signs of wear.

Reduce your loads and cut back on the gas.

Maybe try a H2 buffer and keep the rest of your set-up.

[Cajuntransplant]

Cajun,
Do your loads fall in and out of chamber with gravity only? If you have to apply slight finger pressure to "seat" your rounds, will they fall out without help?

Redraider

I checked this last night and loaded rounds easily slide into the chamber and fall out without any help.

[Cajuntransplant]

These are my thoughts as well.

If you have a new bolt watch for a wear pattern on back of the lugs. The lugs should show equal signs of wear.

Reduce your loads and cut back on the gas.

Maybe try a H2 buffer and keep the rest of your set-up.

Ok I cleaned the old bolt head and noticed a bunch of irregular wear. The lugs closest to the extractor have enough wear on the face and sides of the lugs to have the coating rubbed off and be shined and polished in a couple of small spots. Lugs opposite extractor have no visible wear marks on the face and barely any along the sides like the others do. This mean my barrel and bolt aren’t lining up properly? That, combined with my hot loads, ultimately causing failure? Or is the wear from the hot load and bad unlock time?

[Randy99CL]

This mean my barrel and bolt aren’t lining up properly? That, combined with my hot loads, ultimately causing failure? Or is the wear from the hot load and bad unlock time?

Yes, the bolt isn't aligned well with the barrel extension. I'd guess the extension is the first thing to check; I'd pull the barrel and take it to a gunsmith who could spin it in a lathe to see if the extension is straight. Even if it is only out by a small amount, guessing maybe less than .010", it could make a huge difference in the lugs seating evenly.

Don't think the hot loads or unlock time could be doing this.

[Kswhitetails]

Your facing a couple possible issues, or both. Either the receiver face needs squared, or the barrel extension is oos. The easiest fix would be to swap the upper and barrel. The barrel of its the only problem you are facing, would have to be replaced with one that’s in spec. You could square the receiver face at home if you get the tool(there are 15 threads on this a quick search will find the info).

[Gusmeister]

Gotta go with Klem on this one. I do not see a problem with your loads in your rifle but, obviously, your bolt does. And your loads may be good in other guns or they may been good without the can. Dunno. But I am pretty sure that if you drop your loads by 100 fps and don't do anything different, your problems should go away.

[BluntForceTrauma]

With the discovery of uneven wear on the bolt, my opinion is that is the biggest problem. A while ago, a guy here on the forum broke something like three bolts in quick succession cuz of that, I believe.

[LRRPF52]

Check the receiver face for square.

Also, you said it's a Satern 18" RLGS. Are you sure it isn't a Satern 18" MLGS?

What's your gas port diameter?

[Cajuntransplant]

Gotta go with Klem on this one. I do not see a problem with your loads in your rifle but, obviously, your bolt does. And your loads may be good in other guns or they may been good without the can. Dunno. But I am pretty sure that if you drop your loads by 100 fps and don't do anything different, your problems should go away.

I’m going to pull the barrel and check extension and make sure receiver face is square. After that I will see what the bolt / barrel companies think too and go from there.

[Cajuntransplant]

Check the receiver face for square.

Also, you said it's a Satern 18" RLGS. Are you sure it isn't a Satern 18" MLGS?

What's your gas port diameter?

Yeah I was mistaken... It’s 18” and mid length gas. Don’t know gas port diameter. Whatever they punched it at is covered by adjustable gas block right now. Never bothered to check gas port diameter.

[Cajuntransplant]

With the discovery of uneven wear on the bolt, my opinion is that is the biggest problem. A while ago, a guy here on the forum broke something like three bolts in quick succession cuz of that, I believe.

Yeah that’s my main concern as well. Especially since first bolt had over 1k over it and now this one broke somewhere around 5-600 and I noticed the wear on it. I emailed the company I got the barrel and bolts from and I’m going to see what they say.

[BluntForceTrauma]

My guess is the bolt is normal. I'd first check uneven mating of extension to barrel, or uneven mating of barreled extension to upper receiver. All this exacerbated by increased pressure of suppressor on top of large-ish port in mid-length gas system on an 18". Sort of a perfect storm. And if your loads really are a little warm. . . .

[Klem]

Well, this snack sure has turned into a three-course meal.

Your loads are hot and hammering those bolts. If you can square the lugs and share the load you might get another 500+rds before the next one cracks. Or...you can take your foot off the accelerator and enjoy shooting that gun until the barrel wears out.

Option A costs nothing.
Option B costs time, effort, probably money and does not address the cause.

All the more technical and involved solutions here are based on the assumption your loads are normal, and they are not.