JP bolt won’t headspace

[Eodbrownguy]

Anyone ever have a JP bolt not headspace? I bought a liberty 12.5 and it came with a bolt. I ordered a Jp enhanced bolt and Manson headspace gauges. The liberty bolt headspaced but the JP did not, closes on the no-go. Just curious if anyone else had the same thing happen to them.

[hill37]

The liberty barrels use a.125 bolt. The Jp has a .136 bolt face recess I believe. http://www.65grendel.com/forum/showthrea...nfographic

[Eodbrownguy]

That would make sense, thanks!

[Eodbrownguy]

So is there a list of who supplies .125 bolts?

[hill37]

Google Columbia river arms.

[hill37]

Looks like I misled you on Columbian river. I thought they still sold bolts but they say they use any good 7.62x39 bolt.

[Eodbrownguy]

Will the JP enhanced extractor work on a .125 bolt?

[LRRPF52]

The liberty barrels use a.125 bolt. The Jp has a .136 bolt face recess I believe. http://www.65grendel.com/forum/showthrea...nfographic

Since when did Liberty start using .125" bolt face depth?

Every Liberty barrel I've seen or installed used a .136" face depth.

[centerfire]

Their site says Grendel 2. Why change the bolt in the first place?

[Texas]

I have 3 linerty barrels and they are all .136 bolts. When we were mass producing M16s, occasionally we would have a combinaton that would not headspace. We would try up to three different bcgs to obtain proper headspace before the upper would be set asside.
The only way I can explain it is thar barrels, bolts and barrel extensions all have +/- tolerances, and the headspace problem arose from the various parts being close or at max tolerance variations.

[hill37]

MY mistake I thought Liberty barrels were the Satern barrels with the .125 bolt face. That's what a 70 year old memory does to you. Sorry about that I'll double check from now on.

[Eodbrownguy]

The bolt I have looks like a maxim arms and the liberty site says .136, with this being said, would it lead one to believe the bolt is out of spec?

[LRRPF52]

MY mistake I thought Liberty barrels were the Satern barrels with the .125 bolt face. That's what a 70 year old memory does to you. Sorry about that I'll double check from now on.

Satern has been using .136" bolt face depth from the start.

.125" face depths were used by Model 1 Sales and BHW for a while (they break extractors and the Model 1 Sales bolts in their 6.5 Sporter were often worthless).

Everybody in the industry with a good reputation is using .136" face depth bolts, with maybe the exception of one company who changed names, don't even know their status anymore.

[LRRPF52]

The bolt I have looks like a maxim arms and the liberty site says .136, with this being said, would it lead one to believe the bolt is out of spec?

What's the face depth and lug lengths on the JP bolt? Doubtful the JP bolt is out of spec.

What's the variance on the Manson gauges between GO and NO-GO?

[NugginFutz]

Their site says Grendel 2. Why change the bolt in the first place?

Grendel II, with respect to Satern / Liberty, is referring to their chamber modification - NOT the bolt.

TYPE II is BHW's unfortunate contribution to the Grendel world of regrettable terms, which is something they introduced to distinguish between their barrels headspaced for the .125" bolts (AKA Type I) and the barrels headspaced for the .136" bolts, which are used by Alexander Arms, Les Baer, etc. etc. (AKA Type II).

In short:
Type I and Type II are BHW names for Bolt depth.

Grendel II is Steve Satern's name to identify his barrel which is chambered WITHOUT the SAAMI compound throat.

[Eodbrownguy]

What's the face depth and lug lengths on the JP bolt? Doubtful the JP bolt is out of spec.

What's the variance on the Manson gauges between GO and NO-GO?

Now I have to buy batteries for my calipers, lol

[centerfire]

Why do you want to change the bolt in the first place?

[Eodbrownguy]

I’m not a fan of the finish, the extractor seems fairly weak in it. I’m also weary about the thickness of the material supporting the rim. I don’t know what bolt Liberty supplies with their barrels but it looks like the maxim. I know JPs quality and what materials they use. So I want to go from an unknown to a known, If that makes any sense

[A5BLASTER]

I’m not a fan of the finish, the extractor seems fairly weak in it. I’m also weary about the thickness of the material supporting the rim. I don’t know what bolt Liberty supplies with their barrels but it looks like the maxim. I know JPs quality and what materials they use. So I want to go from an unknown to a known, If that makes any sense

Take a few pics of the bolt, I have 2 maxim bolts in my safe, I will compare them and see if I find anything that matches.

But to behonest, I would just keep the JP bolt and return the Liberty setup for refund and spend my money on a sammi chambered barrel and use that JP bolt with it.

Edit to add.

All 6.5 grendel bolts with have the same sidewall thickness where it supports the case rim.