JP chambers question...

[thefitter]

In my reading up on JP it was mentioned more than once that they had "tight" chambers. I'd really like more details on this. Was this in all calibers? My intention is to go with .308

Has any body measured their chambers length? Or fired case necks?

I asked Ben (great guy!) at JP but he did not have any chamber specs. He suggested I send an e-mail to JPs engineer, but when I asked for chamber dimensions on their .308 builds the response I got back was not very inclusive.

Literally one line-"Our barrels use a 7.62 NATO chamber".

I resubmitted my question with more specifics and an example, but have not heard back. In the mean time does anybody here have any data they could share?

FYI this build will never see anything but handloads, not even FGMM much less surplus.

One more question, who is the main guy at JP? Is there a George like at GA?

Thanks

 

[jevan126]

JP stands for John Paul who is the owner and commander in chief.

 

[EchoDeltaSierra]

From what I understood when I ordered mine, because it's a gas-gun and machines to the SAAMI spec, it follows their deminisions. Take a look at http://www.saami.org/specifications_and_information/publications/download/206.pdf (page 66 print number, or 72 in the PDF file).

From my experience, they are tight to spec. I've just (today) finished my 'break in' process on my LRP-07 and can say after 300 rounds of M80 she's running smooth and reliable. It was even more fun of a process as breaking in my nice 1911.

 

[800mZero]

The chambers are tight to spec. 7.62mm and 223 wyde. This allows for the use of more types of ammunition.

 

[Kiba]

I'm using standard Redding Type-S FL bushing dies for both my 6.5CM LRP-07 and my .223 SCR-11. No chambering or extracting issues relating to resizing so far, the batch of brass for the LRP-07 is on load #3 and the brass for the SCR-11 is on load #5. I bump the shoulder back .0015"-.002" compared to a couple of "example" cases that were fired with the gas block shut off to get a good representation of the chamber.

 

[FALex]

shit, I just sent an email to Benny at JP regarding whether I need a small base die for this particular issue. Looks like I'll be trying to get a JP Engineer on the horn today...I'll keep you all updated. Although, I was never able to get through their main line when I wanted to place my initial order, so I don't know if that'll change? I guess we'll see...

 

[odonnks]

I've read the same thing so when I ordered my JP I also purchased their case gauge.

Fast and simple to use as a go no-go gauge. Also purchased their bore guide. I have others but like how theirs is machined to slide in place of the bolt.
JP - Gunsmithing and Maintenance

As a high end rifle my intended use will most always be with match grade ammunition. I have other semi-auto 308's if I want to go and shoot steel case or lower less consistant ammunition.

Truth is you can get sub MOA with a M&P10 and good ammunition.

Firearm accuracy to me is like when I used to race. A threshold can be reached, in this case accuracy and consistency, for a relatively low cost but to go a bit further the cost goes up a good bit.

 

[thefitter]

From what I understood when I ordered mine, because it's a gas-gun and machines to the SAAMI spec, it follows their deminisions. Take a look at http://www.saami.org/specifications_and_information/publications/download/206.pdf (page 66 print number, or 72 in the PDF file).

From my experience, they are tight to spec. I've just (today) finished my 'break in' process on my LRP-07 and can say after 300 rounds of M80 she's running smooth and reliable. It was even more fun of a process as breaking in my nice 1911.

Thanks.

Page 66 is .308 Win, not 7.62 nato

 

[thefitter]

I've read the same thing so when I ordered my JP I also purchased their case gauge.

Fast and simple to use as a go no-go gauge. Also purchased their bore guide. I have others but like how theirs is machined to slide in place of the bolt.
JP - Gunsmithing and Maintenance

As a high end rifle my intended use will most always be with match grade ammunition. I have other semi-auto 308's if I want to go and shoot steel case or lower less consistant ammunition.

Truth is you can get sub MOA with a M&P10 and good ammunition.

Firearm accuracy to me is like when I used to race. A threshold can be reached, in this case accuracy and consistency, for a relatively low cost but to go a bit further the cost goes up a good bit.

That's interesting that they make a "gizzy" chamber comparator case gauge. I have them made for my custom chambers.

 

[The Lawn Ranger]

If you reload for the LRP-07 in 6.5 CM, you WILL need a small base die.

I had John Whidden make me one based on a fired case. Great dies.

 

[PSYOPS]

If you reload for the LRP-07 in 6.5 CM, you WILL need a small base die.

I had John Whidden make me one based on a fired case. Great dies.

Would a body die fix this or is the Whidden die the only solution???

-Thanks!

 

[The Lawn Ranger]

Would a body die fix this or is the Whidden die the only solution???

-Thanks!

I am not sure about the body die as think this is meant to push the the shoulder back when you neck size only (bad idea for
Auto-loader)

RCBS also makes a SB AR die which will work and it is only half the price of the custom Whidden die.

 

[PSYOPS]

^^^^Thanks Lawn Ranger!!^^^^^

 

[FALex]

yep, Benny over at JP confirmed it. He said the small base die is needed for most gas guns. I never knew that, come to think of it, I have never shot any .223 reloads through any of my other AR's...oh well. It never seems to end.

 

[thefitter]

yep, Benny over at JP confirmed it. He said the small base die is needed for most gas guns. I never knew that, come to think of it, I have never shot any .223 reloads through any of my other AR's...oh well. It never seems to end.

Thats why I want to see chamber specs on these. I don't use a small base die on any of my M14s, M1As, Colt AR, AKs etc.,

 

[GentleBen]

John Paul told me personally that in his .223 Wylde chambers he highly recommends a Dillon FL Carbide die. That is what he uses in his three-gun ARs because it is inherently a small base die. Pricey at $125 for a single sizing die but he claims that and his JP .223 (red) gauge will solve most if not all reloading concerns. He is also a huge fan of Ramshot TAC powder in both .223 and .308.

I do not know for sure about other calibers, but I would use a Redding small base die for auto loaders.