I need a 7.62x39 AR-15 bolt. I would prefer a Leitner-Wise ACB (1st choice) or Colt (2nd choice). If anyone here either has one to sell or knows a source where I can get one, please contact me.

L-W has evidently improved their design and is having to wait on their supply of unobtainium before they can begin manufacture.

Has anyone had any problems at all with the 7.62x39 L-W ACB's or were all the reported problems with the 5.56 version?

Quoted: I need a 7.62x39 AR-15 bolt. I would prefer a Leitner-Wise ACB (1st choice) or Colt (2nd choice). If anyone here either has one to sell or knows a source where I can get one, please contact me. L-W has evidently improved their design and is having to wait on their supply of unobtainium before they can begin manufacture. Has anyone had any problems at all with the 7.62x39 L-W ACB's or were all the reported problems with the 5.56 version?

I have been hunting for a COLT 7.62x39 bolt forever!  I bought one of LW's ACB's for the 7.62x39 and it works very well.  However, I use my COLT bolt primarily.  And you are correct, that all the problems with ACB were the 5.56 variety.  However, that doesn't mean that the same problems don't exist in the 7.62x39 version.  The problems just haven't surfaced since there are not that many 7.62x39 rifles out there that are seeing the same use as the 5.56 rifles.

Have you considered using an Alexander Arms bolt.  The Beowulf and the Grendel use the same size rim as the 7.62x39 and AA has never been accused of putting out junk.

Quoted: Have you considered using an Alexander Arms bolt.  The Beowulf and the Grendel use the same size rim as the 7.62x39 and AA has never been accused of putting out junk.

AA bolts are excellent but cannot be used with 7.62x39.

Though the rim dia. is the same, the bolt face depth is different (I don't remember which is the deeper).

So 7.62x39 bolts will give improper headspace with the AA family of cartridges and an AA bolt will give improper headspace with 7.62x39.

Have you tried Numrich.....

www.e-gunparts.com/dept.asp

Quoted: Though the rim dia. is the same, the bolt face depth is different (I don't remember which is the deeper).

 The AA bolt is 11 thousandths deeper if I recall correctly. You could use it for 7.62X39 if you were cutting the chamber with a reamer. Just cut the chamber 11 thousandths shallow. I don't know why you would want too though. Cutting the bolt deeper will make it weaker, not stronger. A very good educated guess is that its a CMT 7.62X39 bolt cut 11 thousandths deeper. I'd rather have the normal cut CMT bolt. AA says its too improve extraction. It seems more like a dodge too ensure you use their parts. Or make it difficult for anyone else trying to cut chambers. Actually it'd be pretty simple to work around this dodge. M9

Brazos - I've been watching your posts as I'm also building a 7.62x39mm upper.  I understand your search for quality, but I think I might break down a buy a Del-Ton or M1S bolt.  

Have you found any feedback on the Del-Ton or M1S 7.62x39mm bolt?  

Quoted: Quoted: Though the rim dia. is the same, the bolt face depth is different (I don't remember which is the deeper).  The AA bolt is 11 thousandths deeper if I recall correctly. You could use it for 7.62X39 if you were cutting the chamber with a reamer. Just cut the chamber 11 thousandths shallow. I don't know why you would want too though. Cutting the bolt deeper will make it weaker, not stronger. A very good educated guess is that its a CMT 7.62X39 bolt cut 11 thousandths deeper. I'd rather have the normal cut CMT bolt. AA says its too improve extraction. It seems more like a dodge too ensure you use their parts. Or make it difficult for anyone else trying to cut chambers. Actually it'd be pretty simple to work around this dodge. M9

I'm using an existing Colt barrel, so the option of cutting the chamber shallow isn't there. Besides, non-standard headspacing in a quickchange platform like the MGI Hydra sounds like an accident waiting to happen.

Quoted: Brazos - I've been watching your posts as I'm also building a 7.62x39mm upper.  I understand your search for quality, but I think I might break down a buy a Del-Ton or M1S bolt.   Have you found any feedback on the Del-Ton or M1S 7.62x39mm bolt?

I haven't seen any feed back on the Del-Ton or Model 1 Sales bolts. All the threads I've seen related to best 7.62 bolt have been between L-W and Colt.

It is my understanding that Colts are CMT's that have been shot peened and magnafluxed (MPI). Regular CMT's may or may not be MPI'd, but will not be shot peened. MPI is only an inspection technique to cull flawed bolts - those that developed microcracks during heat treat or manufacturing. Shot peening greatly increases fatigue resistance by placing the surface in residual compressive stress. This makes it harder for the surface to reach a high enough tensile stress during operation for fatigue cracks to initiate. Since AR bolts, particularly in 7.62, tend to fail in fatigue, I consider this a big deal.

I don't know if L-W ACB's are shot peened or not. But since they have an even better reputation for longevity than Colt, I have to assume that they either do shotpeen, or their modified design reduced the tensile stresses below the fatigue crack initiation threshold.

Quoted: .... And you are correct, that all the problems with ACB were the 5.56 variety.  However, that doesn't mean that the same problems don't exist in the 7.62x39 version.  The problems just haven't surfaced since there are not that many 7.62x39 rifles out there that are seeing the same use as the 5.56 rifles.

What were the problems with the ACB?  

What were the problems with the ACB?

It is my understanding that they were making a tool clearance undercut at the bottom of the bolt face and 5.56 rims sometimes got caught on it, causing a jam.

Someone correct me if this is incorrect.

They have since redesigned it to eliminate the problem, but are having to wait on the material they make the ACB from.

Quoted: MPI is only an inspection technique to cull flawed bolts - those that developed microcracks during heat treat or manufacturing.

 There is a little more too it than that.  Colt shotpeened the bolts, then proof tested with  "Blue Pills" & then magnufluxed. This magnafluxing after proof firing makes a difference. If you buy the same bolt without the proofing & MPI you might be buying the bolt that would have failed if it had been subjected to the testing. Anyone who builds racing engines that are restricted to "stock" parts does the same things. They usually prefer used pre-stressed seasoned components. Then they magnuflux it. You stress it first, then you magnuflux it. An engine builder restricted to "stock" rods may go through 30 or 40 to pick 8 that are suitable. Newbies want new rods. The really good rods are the ones that didn't fail in the engine the other guy blew at 9,000 rpm. You get them & check them. They've been pre-stressed & didn't fail. M9

Quoted: Quoted: MPI is only an inspection technique to cull flawed bolts - those that developed microcracks during heat treat or manufacturing.  There is a little more too it than that.  Colt shotpeened the bolts, then proof tested with  "Blue Pills" & then magnufluxed. This magnafluxing after proof firing makes a difference. If you buy the same bolt without the proofing & MPI you might be buying the bolt that would have failed if it had been subjected to the testing. Anyone who builds racing engines that are restricted to "stock" parts does the same things. They usually prefer used pre-stressed seasoned components. Then they magnuflux it. You stress it first, then you magnuflux it. An engine builder restricted to "stock" rods may go through 30 or 40 to pick 8 that are suitable. Newbies want new rods. The really good rods are the ones that didn't fail in the engine the other guy blew at 9,000 rpm. You get them & check them. They've been pre-stressed & didn't fail. M9

And now we have proceeded to where we started. Yes, for a number of very good reasons, Colt and L-W ACB's are the best 7.62x39 bolts on the planet.

Now the big question remains - anyone got an extra lying around that they'll sell me or know where I can get one?

Recently had a long conversation with Tom Lyons of MGI regarding the use of AA bolt in 7.62x39. He in turn had a long conversation with Bill Alexander. I am in the middle of similar conversations with Bill. I think you might be incorrect in assuming the AA 6.5 Grendel bolt won't work as a replacement for 7.62x39. I won't reprint Bill's answers to my questions in a public forum as I know he monitors these threads and apparently has chosen not to air his view.  I'll summerize in confidence to anyone who'd like to contact me off board. In the mean time I'd invite Bill to chime in at any time.

-Glen

Quoted: What were the problems with the ACB? It is my understanding that they were making a tool clearance undercut at the bottom of the bolt face and 5.56 rims sometimes got caught on it, causing a jam. Someone correct me if this is incorrect. They have since redesigned it to eliminate the problem, but are having to wait on the material they make the ACB from.

Thanks, I wasn't aware of that issue.

Quoted: Recently had a long conversation with Tom Lyons of MGI regarding the use of AA bolt in 7.62x39. He in turn had a long conversation with Bill Alexander. I am in the middle of similar conversations with Bill. I think you might be incorrect in assuming the AA 6.5 Grendel bolt won't work as a replacement for 7.62x39. I won't reprint Bill's answers to my questions in a public forum as I know he monitors these threads and apparently has chosen not to air his view.  I'll summerize in confidence to anyone who'd like to contact me off board. In the mean time I'd invite Bill to chime in at any time. -Glen

Glen,

E-mail sent

Quoted: Quoted: Recently had a long conversation with Tom Lyons of MGI regarding the use of AA bolt in 7.62x39. He in turn had a long conversation with Bill Alexander. I am in the middle of similar conversations with Bill. I think you might be incorrect in assuming the AA 6.5 Grendel bolt won't work as a replacement for 7.62x39. I won't reprint Bill's answers to my questions in a public forum as I know he monitors these threads and apparently has chosen not to air his view.  I'll summerize in confidence to anyone who'd like to contact me off board. In the mean time I'd invite Bill to chime in at any time. -Glen Glen, E-mail sent

Eyes on for reply

Quoted: I think you might be incorrect in assuming the AA 6.5 Grendel bolt won't work as a replacement for 7.62x39. -Glen

  If as reported here in an earlier thread, its a CMT 7.62X39 bolt with the recess cut 11 thousandths deeper, yes you could make it work. If you were cutting the chamber, you could just cut it .011" shallow. If you are using a barrel with the chamber already cut, you might juggle barrel extensions to get headspace closer too spec. If you were using handloads only, you could easily adjust your dies to make it work. I just don't understand why anyone would want to do this. The reason seems to be that they consider this bolt superior to a regular CMT 7.62X39 bolt. I've seen no evidence that this is so. Cutting it deeper would make it marginally weaker, or so logic would seem.
I'd go with the regular CMT bolt & have it shotpeened, then test it with some heavy loads, remotley from cover & then magparticle test it. That should be very near to identical to a Colt bolt, if it passes the magnufluxing. M9

PS If you really want a Colt bolt badly enough, you could buy an entire Colt 7.62X39 AR & rob the bolt out of it. I see them quite frequently at gun shows for sale, both used & new in the box. They ain't exactly cheap though. I imagine you could replace the bolt with a CMT bolt & resale it & recoup most of your expended cash though.

Quoted: If as reported here in an earlier thread, its a CMT 7.62X39 bolt with the recess cut 11 thousandths deeper, yes you could make it work.

What do you mean, "as reported earlier"? You mean: As rumored earlier . . . by you!

For the record: CMT does not make AA's .50 Beowulf and 6.5 Grendel bolts. Period.

And I'm still not entirely convinced that CMT even makes 7.62x39 bolts, as far as that goes. What makes you think they do?

John

==========
6.5 Grendel: World's Best Combat Cartridge

Quoted: What do you mean, "as reported earlier"? You mean: As rumored earlier . . . by you! John ========== 6.5 Grendel: World's Best Combat Cartridge

 No there was a previous poster that stated he called CMT & even gave the name of his contact at CMT. The contact gave detailed specs for the bolt provided. I do rember they specified the use of the same steel that CMT had used in producing Colt 7.62X39 bolts. I suspect they have been made by various subcontractors as in lowest bidder. M9

Quoted: And I'm still not entirely convinced that CMT even makes 7.62x39 bolts, as far as that goes. What makes you think they do? John ========== 6.5 Grendel: World's Best Combat Cartridge

  When the falling out between CSS & AA first occured Arne clearly stated that his uppers used CMT 7.62X39 bolts. It was also shown & listed as a seperate item for purchase on his website. I haven't checked to see if its still there. But you could if you have doubts. I also know that you & him are well aquainted, why don't you ask him. M9

Quoted: That's all I know about it, folks.

 I belive in a previous conversation with you that you told me MGI was devolping a high-strength 7.62X39 bolt & in the interim that MGI was using the CMT 7.62X39 bolt. Any confirmation of that? And how is the work on the high-strength bolt coming? Thanks M9

Quoted:Our bolt will not be in the price-competitive range with these other bolts, and will cost significantly more money. We may see something like this by mid-summer.

 If your bolt is significantly stronger than a normal 7.62X39 bolt then its worth more. I want one ASAP. I feel I must tell you though that I don't really see your project of getting 7.62 NATO into the AR-15 as feasable. I hope I'm wrong though. I do have some thoughts on how your work in this area would be useful if I'm proved right however. M9

 PS I love your lowers. Now if you could work on the price a little.

Quoted: Regarding what we use now for our 7.62x39 bolts, we stock whatever we can get supplied with from other manufacturers. We do not make the normal bolts for any rifle caliber options at this time. We outsource all the bolts, currently. CMT and DPMS have both supplied us in the past, for 7.62x39 bolts.

 I suspect that AA's bolt procurement process is VERY SIMULAR too your own, with the exception of cutting the case head recess deeper. M9

Quoted: Yes I understand, the 308 project is very ambitious, and it has given alot of difficulty in development. Parts strength has been the main problem, and as we improve one part, the next one down the line starts to show signs of stress. So, this project is not for the faint-of-heart. We've proven that it can work, but we haven't proven that it can last long enough for commercial production yet. However, regardless of how that project comes out, there are these spin-offs which we've learned thru our development process, which can benefit people in other ways. R&D is an interesting world, and we don't always get what we want. But, sometimes we do.

  Then I take it the main hurdles to overcome are in parts strength, not in shoehorning the M14 mag in?  I realize it would never have the commercial appeal of 7.62 NATO, but I do belive a 6.5 Carcano rd would fit into a M14 mag & not put as much stress on the components. My interest in these matters are in devolping Designated marksmen weapons on the AR. I'm limted however too issue M16A-2 lowers so this isn't feasible for me, but would be for MGI. Norma still loads this rd. It has a base dia only slightly larger than 7.62X39 & considerably less than 7.62 NATO & absoulutley spanks the 6.5 PPC improved or otherwise. M9

Quoted: Very interesting that you mention the 6.5 Carcano, because we are developing that right now, for the magwell that accepts the M14 magazine. From a 20" barrel, and depending on powder charge, we could see 2500 fps from a 142gr SMK in that caliber from our platform with a normal 7.62x39 bolt at 45k psi. With the addition of the high strength bolt, we could push Nato pressures, and get quite a bit more speed out of it. You're right, it would make a helluva DMR package!

 I'll buy one for my personel use, when you get the high strength bolt up & running. However professionally I wouldn't be allowed to use it, since it requires an aftermarket lower. If I had one of your high strength bolts, I'd be working on a shortened version for an issue lower. Might even use a shortened 35 Remington case as its much more available from American suppliers & is nearly identical to 6.5 Carcano. M9

Quoted: From a 20" barrel, and depending on powder charge, we could see 2500 fps from a 142gr SMK in that caliber from our platform with a normal 7.62x39 bolt at 45k psi. With the addition of the high strength bolt, we could push Nato pressures, and get quite a bit more speed out of it.

 Hmm, I don't know what pressure Norma loads the Carcano too, but I can't imagine it being too high, as a Carcano is not a very strong action. If a normal bolt won't handle the Norma factory load though, I can't imagine you selling it untill the high strength bolt is available. You could neck it to 7mm or 30 cal & sell ammo loaded to the correct pressure though. All in all though I'd deem it wise to just devolp in-house prototypes untill you get a better bolt. M9

I suspect that AA's bolt procurement process is VERY SIMULAR too your own, with the exception of cutting the case head recess deeper. M9

Once again I'll question that statement as likely incorrect. Have you spoken with Bill Alexander? I have, and he states that he has been the manufacturer of over 9000 Gendel bolts, and that they are not "carved out" 5.56 units. This would appear to be a manufacturing process not a procurement process.

Quoted: Once again I'll question that statement as likely incorrect. Have you spoken with Bill Alexander? I have, and he states that he has been the manufacturer of over 9000 Gendel bolts, and that they are not "carved out" 5.56 units. This would appear to be a manufacturing process not a procurement process.

 I know he serves great Kool-Aid. AFAIK he doesn't manufacture anything. He procures parts from various suppliers & cases from Lapua. He assembles rifles, uppers & loads ammo. I guess he's technically a weapon manufacturer & an ammo manufacturer. But I'm pretty sure he is not a bolt manufacturer. There are not many actual manufacturers of Bolts for the AR. Most assemblers procure them from a handfull of sources. Its my guess that even Colt wasn't a bolt manufacturer untill they bought Diemaco & the only reason Diemaco didn't buy CMT bolts like most everyone else is because Canadian law required that their service rifle be 100% made in Canada. M9

Quoted: Once again I'll question that statement as likely incorrect. Have you spoken with Bill Alexander? I have, and he states that he has been the manufacturer of over 9000 Gendel bolts, and that they are not "carved out" 5.56 units. This would appear to be a manufacturing process not a procurement process.

 I bet what he really said was he was the manufacturer of over 9000 Grendel uppers that included a bolt. M9

Quoted: and that they are not "carved out" 5.56 units.

 In one sense I'm pretty sure thats exactly what they are. It depends on your definition of "carved out 5.56 units". When PPC ARs were first being devolped, they were indeed carved out military 5.56 units. When you carve them out of an existing 5.56 bolt you cut through the external layer of hardened steel. Such bolts were notorious for failing. Then Colt devolped the 7.62X39 AR which basically uses the same case as the PPC. As such these bolts were suitable as-is for the PPC AR & didn't need any carving to cut through the hardened skim. They made much better PPC bolts than reworked 5.56 bolts. But even these are really only carved out 5.56 bolts. The only difference is that the manufacturer( Probrably CMT) carved them out before heat treatment. They are much better than reworked 5.56 bolts & I'm quite sure he doesn't use reworked 5.56 bolts. But what the PPC & 7.62X39 ctgs really need is a substantially stronger bolt, either through an increase in size or better metal. M9

PS AFAIK All AR bolts except the OLY WSSM series use the same basic bolt that Eugene Stoner originally designed to be military strength for the puny little 222 Remington. Since then it has been adapted mainly through carving it out to fit any other ctg used in an AR. That includes 5.56, 6X45, 7.62X39, 6.8, & the PPC ctgs. Thats asking a lot out of a bolt designed for 222 Remington in an airweight configeration. M9

Quoted: But what the PPC & 7.62X39 ctgs really need is a substantially stronger bolt, either through an increase in size or better metal.

Correct on both counts, and if you add in a third factor, better heat-treat, then you've got AA's bolt rated for use in 50B/65G. (And before you object, the increase in size is minor, and is in a certain specific dimension, but it's there --- and it adds strength.)

You are also correct that they subcontract their bolts, but nobody claimed they didn't and that's only a correction to Shotgun1's mistaken impression.

John

P.S. It's interesting (from a psychiatric point of view) that I can tell you plainly that AA bolts are not made by CMT, and yet a couple posts later you reiterate that you suspect AA bolts are made by CMT.

Let's try it again, just for fun. . . . So when I say, for the record, that AA bolts are not made by CMT you, like a broken record, say. . . .

==========
6.5 Grendel: World's Best Combat Cartridge

Quoted: Quoted: But what the PPC & 7.62X39 ctgs really need is a substantially stronger bolt, either through an increase in size or better metal. Correct on both counts, and if you add in a third factor, better heat-treat, then you've got AA's bolt rated for use in 50B/65G. (And before you object, the increase in size is minor, and is in a certain specific dimension, but it's there --- and it adds strength.)========== 6.5 Grendel: World's Best Combat Cartridge

 Looks like a 7.62X39 bolt, walks like a 7.62X39 bolt, Quacks like a 7.62X39 bolt. 7.62X39 bolts aren't known for being overly strong. If the bolts are so strong why do they keep the pressure low? M9

MGI, When your imroved bolt with the 7.62x39/6.5grendel/50 beowolf bolt face dia.is manufactured,will it have the boltface recess of the AA desighn.Or will it be yhe same as the Colt and DPMS 7.62x39 bolts in regards to the depth of the boltface recess?

Quoted: Let's try it again, just for fun. . . . So when I say, for the record, that AA bolts are not made by CMT you, like a broken record, say. . . . ========== 6.5 Grendel: World's Best Combat Cartridge

 Lets clarify that statement. Are you saying that none of the 6.5 Grendels in existence today use a bolt from CMT? Or are you saying that at the present time AA has found a lower bidder & they no longer make them? M9

Quoted: (And before you object, the increase in size is minor, and is in a certain specific dimension, but it's there --- and it adds strength.) ========== 6.5 Grendel: World's Best Combat Cartridge

 So if its really made out of a denser metal & its larger, then it should weigh more than a military 5.56 bolt, correct? Why don't you weigh one of yours & I'm sure someone else on this forum has a Colt 5.56 bolt & a scale. Post the results & lets see. I'm betting the 5.56 bolt is heavier because it has more meat left in it. Put up or shut up. M9

 PS Be sure to clean them first we aren't interested in the weight of carbon deposits. I'm assuming you know how too remove your bolt, clean it & weigh it. If you need instructions let me know.

Quoted: Lets clarify that statement. Are you saying that none of the 6.5 Grendels in existence today use a bolt from CMT?

Correct. No AA 6.5 Grendel build nor a licensed 6.5 Grendel build has ever used a CMT bolt. Ever. Period. Please read that again three more times so you don't bring it up again two posts later. Thank you.

John

==========
6.5 Grendel: World's Best Combat Cartridge

Quoted: Quoted: Lets clarify that statement. Are you saying that none of the 6.5 Grendels in existence today use a bolt from CMT? Correct. No AA 6.5 Grendel build nor a licensed 6.5 Grendel build has ever used a CMT bolt. Ever. Period. Please read that again three more times so you don't bring it up again two posts later. Thank you. John ========== 6.5 Grendel: World's Best Combat Cartridge

 How about 1 post later. Thank you for clarifying your position on this. Pardon me if I consider that you might not have the nessasary knowledge too make it. It certainly goes against evidence posted in a prior thread. I also know that Mr. Alexander himself has stated in a public forum that licensees are free to build 6.5 Grendels with 7.62X39 bolts from any source they desired but that he strongly encourged the use of the bolt he provides. I'm also aware of the fact that Arne of CSS, who even by your own websites historical info is credited with this chambering in a predesser to AA manner, once made uppers & rifles marked & advertised as 6.5 Grendel. On the day that he redid his website to show them marked as 6.5 AR he stated that they used a CMT 7.62X39 bolt. He also stated that they had long used this bolt in their builds & had complete confidence in it. Long before their licensing fallout Arne had stated (once again on your website) that the bolts for 6.5 Grendel were 7.62X39 bolts with a different extractor. I do belive that CSS still has a banner at the top of your website as a 6.5 Grendel provider. Correct or not? I'm sorry if I come across as abrasive here, but in having many extended conversations with you in the past, its my veiw that you have a lot more knowledge of website fabrication & maintenance than of weapon fabrication, maitenence, & use. But you do seem willing to learn. I suggest you lay off the Kool-Aid for a few days. Perhaps MGI will complete devolpment of their high strength bolt. Then perhaps someone can devolp a 6.5 PPC imp. +P & most of your dreams won't be inhibited by an inherently weak bolt. Perhaps someone will truly make a Hi-Cap mag for this caliber instead of the 5.56/6.8 retreads that you insist upon calling engineered from the ground-up to be 6.5 mags. Oh 1 more question, military 5.56 bolts are proofed with 70,000 psi proof loads, do you know what psi level these uber-bolts are proofed at? Are they even proofed at all? I'm completly open too the possibility that this bolt is better, but I haven't seen a shred of evidence that would lead me to belive it is. In order too convince me, you are going to have too come up with something a little better than "cause Bill says so". M9

PS Have you fiquired out how too get that bigger Uber-bolt built from Unobtanium out to weigh it yet?

Quoted: In order too convince me. . . .

Incredible. . . . I feel like I just punched the "tar baby" and realized my fist is stuck in the gooey mess.

M9, M9, M9. . . . I'm tired, I got work to do, I got a family and a dog. . . . Ya wore me down. I'm not gonna argue. i'm going to let your last post stand unchallenged. You get the last word. . . .

John

==========
6.5 Grendel: World's Best Combat Cartridge

Quoted: M9, M9, M9. . . . I'm tired, I got work to do, I got a family and a dog. . . . Ya wore me down. I'm not gonna argue.

 Is that big bolt, so big its stuck in there & you can't get it out? M9

According to the Grendel forum the bolt recesses on CMT bolts are .125 and the recesses on AA bolts are .136, which surely means you’re only going to have a headspace issue if you change out a CMT bolt on a CSS gun for an AA bolt.  If you reload this shouldn't be a problem, because you would just neck size after the first firing. While this doesn’t resolve the issue of whether the 7.62x39 bolts made by CMT, DPMS and Colt are strong enough to handle the Grendel’s pressure it is concerning for makers like AA who need to ensure there is one common spec.  On the other hand, Gunblast’s review on AA’s .50 Beuwolf clearly states that that gun uses a standard 7.62x39 bolt.  How confusing!  

Read this site for long enough and you really can accumulate a complete database of utterly bollocks information.

Beowulf bolts and Grendel bolts are identical in design. The case head recess is 0.136".

The steel employed for the manufacture of the bolt is not Carpenter 158. This steel has a lower Kic value than required for this bolt design. They are cryo treated.

No bolts have failed on Beowulf rifles under correct usage in 7 1/2 years of production.

No bolts have failed on Grendel rifles under correct usage in 3 1/2 years of production.

The bolts are not manufactured nor have they ever been by CMT.

I will now sit back and wait to hear from those who obviously have a much better grasp of metallurgy, fatigue analysis, stress analysis and weapon design. Perhaps I will learn were I went wrong in the design and also how and where I should procure the parts.

Bill Alexander

Grendelizor - In this instance we should bow to the superior knowledge that abounds on this forum, and you should not try and argue. It is obvious that any questions that come up here can be more than edequate answered without any input whatsoever from the manufacturer.

I am sure that the interests of those asking the questions will be fully supported by the factual answers that threads like this supply.

Bill Alexander

Bill,

I'm the OP.

One thing I'm wondering about. Your bolt face is .011 deeper than a Colt 7.62 bolt according to what all have posted. Is the distance from the bolt face to the back of the lugs the same as the Colt so that it will still headspace correctly on a Colt 7.62x39 factory barrel, or will the headspace be .011" more, and therefore likely capable of taking a "no-go" gage?

I never intended to start an argument. I just need a strong, quality bolt that will headspace correctly on my 16" Colt factory 7.62x39 barrel.

I had planned on either a Colt or a L-W ACB. But if your Grendel bolts will headspace correctly (take a "Go" gage, but not a "No-Go" gage) on 7.62x39 barrels, then I'll be calling to order one. I have never for a moment doubted the quality of your bolts. Just the suitability for 7.62x39. If I was incorrect about that, I will be very happy.

Quoted: The steel employed for the manufacture of the bolt is not Carpenter 158. This steel has a lower Kic value than required for this bolt design. Bill Alexander

 OK, Lets clarify that statement. Is this just for current production or have previous bolts been used that were Carpenter 158? M9