6.5 g rap bolt

[bj139]

Some development that Colt did on the AR led them to use a .136 bolt depth.
Alexander Arms went with that and here we are.
7.62x39 seems to work fine with a .125 bolt depth.

Greg,
Thanks for all your help with the wildcats on the other site.

[GLShooter]

Some development that Colt did on the AR led them to use a .136 bolt depth.
Alexander Arms went with that and here we are.
7.62x39 seems to work fine with a .125 bolt depth.

Greg,
Thanks for all your help with the wildcats on the other site.

I try. I know that more in the chamber is a better deal, That's one reason why I like the LBC variants that are 0.125. Never had any functional issues or broke a single part yet. I know I'll feed this one on the warm side before I rebarrel it to 243 LBC.

Greg

[Frontier Gear]

Yes it does. That is check mark 2 of 3 in my book. It ain't looking good for the mini now.

I wouldn't worry about it A5. As others have pointed out, the Howa is put together with more detail, time and attention to each rifle. The AR, Savage and RAP take more of a low cost and mass production approach. Each has it's pros and cons. It is easier to get parts and interchange parts with the AR, Savage and RAP than it is for the Howa. However, the Howa feels much more quality than the others as well (with the exception of the LSI plastic parts).

With the Howa the bolt and bolt knob are all machined from one solid piece. The receiver and the recoil lug are machined from one solid piece. The metal finish is excellent. It has fewer parts. It is butter smooth. Overall it is a much nicer barreled action than any RAP or Savage that I've seen. They are done in the old school way. It is a different approach, but not a bad one.

[GLShooter]

So while we've chased this thread all over involving my Ruger, that's not a HOWA, I guess the answer is there is no rhyme nor reason for any bolt face depth consistency?

Greg

[Frontier Gear]

If it's not an AR, I wouldn't worry about it.

[GLShooter]

If it's not an AR, I wouldn't worry about it.

I don't even worry about it when it's an AR. I was just curious if anyone had any insight other than, "Just because it is what it is."

Greg

[Msalm]

So while we've chased this thread all over involving my Ruger, that's not a HOWA, I guess the answer is there is no rhyme nor reason for any bolt face depth consistency?

Greg

Yes, the minimum required for the extractor and ejector to operate properly. As long as function is there, the shortest/least amount of unsupported case head is best. So enough depth for the extractor hook and a chamfer ahead of it so it snaps over the rim into the groove.

[GLShooter]

Yes, the minimum required for the extractor and ejector to operate properly. As long as function is there, the shortest/least amount of unsupported case head is best. So enough depth for the extractor hook and a chamfer ahead of it so it snaps over the rim into the groove.

That's exactly what my opinion was. More support is better in firearms. We learned that in hot loading USPSA pistols decades ago to MAJOR on the 9's and 38 Supers.

I've been shooting wildcats in AR's for years on the 6.5 and 6.8 and everyone of them is 0.125. I've never broken anything on a bolt or experienced any reliability issues and I can assure you they haven't all been mild. I would expect nothing less in a bolt.

Greg

[BluntForceTrauma]

Different extractor design allows different boltface depths. Ruger American uses a sliding plate extractor, common to many bolt gun designs, as opposed to an AR extractor.

Grendel boltface depth was set at 0.136 to allow more meat in extractor to compensate for thicker Grendel rim. Not absolutely necessary, but nice to have for theoretical longer extractor life.

I agree it begs the question, then, why 7.62x39 ARs seem to get by on boltface depths of 0.125 when they use the same cartridge rim. Does extractor breakage seem common in 7.62x39 ARs?

[ricsmall]

Different extractor design allows different boltface depths. Ruger American uses a sliding plate extractor, common to many bolt gun designs, as opposed to an AR extractor.

Grendel boltface depth was set at 0.136 to allow more meat in extractor to compensate for thicker Grendel rim. No absolutely necessary, but nice to have for theoretical longer extractor life.

I agree it begs the question, then, why 7.62x39 ARs seem to get by on boltface depths of 0.125 when they use the same cartridge rim. Does extractor breakage seem common in 7.62x39 ARs?

I don’t think extractor breakage in Grendel is any more common than in 5.56. I don’t have data to back that up, but I’ve read enough of Paul’s posts to confidently say that. He probably has more rounds in the hill from a grendel than most here. I’d rather have the properly engineered extractor than not. I’ve ran some pretty hot loads and have yet to break an extractor, but I have adjustable gas on every Grendel I own or build for buddies. I decrease gas incrementally as I increase powder while load developing as a precaution.