TIGHT JP Chambers - Which Sizing Die for 650?

[JoshF]

Got to try out my new JP Barreled rifle this weekend (actually all jp except receiver set ). It shoots great but the first time I went to clear a live round I had to pull like hell to get the round out. Seems about every round is like this as well. Now we did try the exact same rounds in another AR and it fit with NO issues at all.

I'm not new to rifle reloading but this is the first tight chambered AR I've dealt with. We originally sized all this brass on a Dillon 650 with the die set about 1/4 turn in from touching the shell plate. Even like this the cases would not drop in to a Wilson Case Gauge correctly. Now I've also loaded about 100 rounds on a RCBS Rockchucker with the RCBS standard die set the same way and this still creates quite a bit of stick and makes the rounds difficult but not impossible to extract.

So my question is what die do I use to size rounds for the JP Chamber? I've heard some grind or mill off the bottom of the die slightly, I can do this as well if that's a good solution. I hoping someone has an easy solution as there are way to many of these rifles floating around.. .OH and I tried the same rounds in my Dad's JP barreled rifle too with the same result.

Edited May 4, 2009 by JoshF

[norbs007]

FWIW, having a chance to own four JP uppers (down to two now) I experienced the tight chamber in all of them using the Dillon sizer. Even started a thread about this a while back. I switched to a Redding Small Base sizer die and that seemed to help; although a lot have no issues with the Dillon die. I also load rifle ammo on a single stage.

[el pres]

I use a Lee die and it works just fine ?? Grinding the bottom of the die is for shoulder set

back (headspace) issues and not sticky bases. My JP is not this tight, I would defenitely go

with a small base die in this situation ..

[J-Ho]

I have a Rock River, both JP and RR use Wylde chambers, and had the same problem. I switched to a RCBS small base die. problem solved.

[RH45]

Got to try out my new JP Barreled rifle this weekend (actually all jp except receiver set ). It shoots great but the first time I went to clear a live round I had to pull like hell to get the round out. Seems about every round is like this as well. Now we did try the exact same rounds in another AR and it fit with NO issues at all.

I'm not new to rifle reloading but this is the first tight chambered AR I've dealt with. We originally sized all this brass on a Dillon 650 with the die set about 1/4 turn in from touching the shell plate. Even like this the cases would not drop in to a Wilson Case Gauge correctly. Now I've also loaded about 100 rounds on a RCBS Rockchucker with the RCBS standard die set the same way and this still creates quite a bit of stick and makes the rounds difficult but not impossible to extract.

So my question is what die do I use to size rounds for the JP Chamber? I've heard some grind or mill off the bottom of the die slightly, I can do this as well if that's a good solution. I hoping someone has an easy solution as there are way to many of these rifles floating around.. .OH and I tried the same rounds in my Dad's JP barreled rifle too with the same result.

I have a .223 with a tight chamber and I tried 4 of my friend's sizer dies and the only one that would work was a Lee. I sent my RCBS die back, along with some cases that were fired in the rifle, and they ground down the end of the die, but, I can now actually take it down further than needed if I'm not carefull when I set it up.

You could just send me your JP upper, and I'll send you a different upper that almost any ammo would work in.

[uscbigdawg]

Dillon dies have worked for me since day 1. FWIW, Dillon's 223 dies ARE small base dies.

Rich

[3gunpinoy]

i have used a RCBS small base. worked well

[DougCarden]

I use Redding small base dies, and have a JP case gauge for my ammo as well. If I have a problem it is the brass( never know how many times loaded).

If it drops out of my JP or Dillon gauge then it runs in any of my ARs....Look at the rounds that came out of the chamber and were tight. Is it due to the back of the case(you will see a mark on the case) or is it from the mouth of the case?

This will tell you if it is your case prep or the lack of some crimp....

Good luck,

DougC

[GentlemanJim]

Its not that the cases are too fat...its the shoulder a little too far out

If you push the shoulder back so its at the min. spec on the case gauge..it will run perfect

Jim

[norbs007]

Its not that the cases are too fat...its the shoulder a little too far out

If you push the shoulder back so its at the min. spec on the case gauge..it will run perfect

Jim

+1

[D.carden]

We originally sized all this brass on a Dillon 650 with the die set about 1/4 turn in from touching the shell plate.

I run a JP and use Dillon die's..........But I set the sizing die touching the shell plate (actually cam'ing over about an 1/16th of a turn)........Never had a stuck case. And I dont even own a case gauge....Knock on wood !!!!!!!!..........

[JoshF]

Guys, thanks for all the replies.

The full cartridges I pulled out seem to be touching right at the base of the shoulder. I'll mill down the dillon to see if we can get the desired result out of it. Doesn't seem to be too fat a case as much as it is the shoulder isn't being set back enough.

If that doesn't work well then I think I'll try the Redding Small Base as I've had nothing but good luck with their dies.

Also I did try a few random types of factory rounds and they all dropped right in. definitely something to do with the re sized cases.

Edited May 5, 2009 by JoshF

[mlmiller1]

Josh,

Almost everyone sets their dies to contact the shell plate, not 1/4 turn away from it like you said you have yours set. Make it so that your press kind of "cams" over when you pull the handle all the way down. That should set the shoulder back enough.

MLM

[Chris]

Get the JP case/head space gauge and adjust your dies till the cases drop in and out of the gauge.

The gauge is cut with the Wylde reamer so it matches the chamber.

[ERIC]

I recently started loading 223 with my 650 and Dillon dies for long range ammo only (77 gn SMK) and ran into the same problem with my JP barrel. I loaded a bunch of them and they all passed with Dillion's case guage. While determining a load, I must have shot over 50 rounds and all of them worked just fine. I found out there was a problem during a match (of course) when a round failed to fully chamber. I had to hammer the stock on the ground to get the round out. When I got home, I noticed the die wasn't touching the shell plate even though I could swear I set it touch. I used my barrel to as a case guage and checked all of the rounds which was not fun at all. Almost half of them didn't fall out freely. I'm now stuck with a bunch of rounds I'll have to shoot out of my 556 chambered rifles which I use for full auto fun.

I agree with what others have said. I don't think the round is too fat but the shoulder needs to be sized further down.

This week, I made sure the die is touching the shell plate and then some. I'm going to borrow some bullets from my buddy and try 25 rounds and see if that helps.

[RH45]

I recently started loading 223 with my 650 and Dillon dies for long range ammo only (77 gn SMK) and ran into the same problem with my JP barrel. I loaded a bunch of them and they all passed with Dillion's case guage. While determining a load, I must have shot over 50 rounds and all of them worked just fine. I found out there was a problem during a match (of course) when a round failed to fully chamber. I had to hammer the stock on the ground to get the round out. When I got home, I noticed the die wasn't touching the shell plate even though I could swear I set it touch. I used my barrel to as a case guage and checked all of the rounds which was not fun at all. Almost half of them didn't fall out freely. I'm now stuck with a bunch of rounds I'll have to shoot out of my 556 chambered rifles which I use for full auto fun.

I agree with what others have said. I don't think the round is too fat but the shoulder needs to be sized further down.

This week, I made sure the die is touching the shell plate and then some. I'm going to borrow some bullets from my buddy and try 25 rounds and see if that helps.

If you have enough ammo that's screwed up to make it worthwhile, you can get a body die and run loaded ammo through it to push the shoulders back a little.

[Dan Sierpina]

The shoulder is not being set back sufficiently for chambering. It has nothing to do with the base of the case being too large a diameter. The shell holder should make solid contact with the die, they are made to do that.

[RiggerJJ]

Josh,

You don't need to grind on anything. The Dillon die works fine. Set the sizing die all the way to the shellplate + 1/16 to 1/4 turn.

Also, you MUST use case lube!!!

FWIW, I also use a neck die after the full length sizing die, but I load for several different chambers. The neck die bumps the shoulder just enough to make the Dillon guage easily and have no problems with chambering in any of our ARs, including 2 JPs.

jj

Edited May 5, 2009 by RiggerJJ

[uscbigdawg]

I'm with JJ.

All I do is (with clean brass) is spray with Dillon case lube, shake 'em up (about 50-100 or so in a box and 2-3 sprays), toss it in the hopper and load. Tumble the lube off and then gauge in my JP case gauge.

At setup, the sizing die is touching the plate and then a little "eh" more to give it that little extra.

No jams or issues.

Rich