The PRC die "problem"

[Tac-O]

@Alex Wheeler , I'm very appreciative you've shared so much of your knowledge with the public even when it actually costs you money through your time.

I've got no interest in a PRC at the moment, but I've followed along in this thread the last couple of years so that I could learn something. I ended up using your knowledge from this thread and a couple others on another forum on 284 clickers to help me determine my first wildcat chamber/resizer reamer prints. I think it'll work, but I'm only at 4 reloads. My only worry is I could crack my resizer, but likely not.

284win Peterson brass, 0.499 virgin, 0.0500-501 couple firings
Chamber 0.502 at 0.200
Resizer reamer 0.498 at .200.

I've had a couple stuck cases, but it's generally resolved by cleaning the die and lubing the hell out of the die and my first couple pieces of brass. Die is from a PTG blank and is not hardened.

It's working well so far. Thanks for sharing. I hope to get on your customer wait list someday!

 

[Alex Wheeler]

You did good. Send it out for nitride and then polish it when it comes back. Its will be much smoother. It wont crack. Magnum dies are thinner.

 

[Tac-O]

You did good. Send it out for nitride and then polish it when it comes back. Its will be much smoother. It wont crack. Magnum dies are thinner.

Will do.

I've got a correction on my measurements though. I remembered you saying something about the portion causing clickers not actually being the 0.200 line, so I went and measured again tonight. The others were from memory.

0.499 virgin, 0.500 after 4 firings in front of extractor groove
Chamber 0.502 at 0.200
Resizer reamer 0.498 at .200

Web area ahead of 0.200 line, probably around 0.350 line measures 0.503 fired, 0.5015-0.502 sized.

0.502 sized seems it would absolutely give me issues in my 0.502 chamber and my 0.503 fired brass shouldn't even chamber. But I've felt no extraction issues.

Checked my sizer die and it's real close to 0.498 at bottom, hardly any chamfer there, and brass runs all the way in nearly to extractor groove.

I've been running them 1.0 grain under first light sign of ejector mark. Wouldn't think that would be too hot and is obviously ok since primer pockets are still tight and head in front of groove hasn't gone past 0.500 yet.

I think either my chamber got cut sloppily or my reamer isn't actually the dimension I specd it at. Hmmmm.

I'll have to keep going on this brass to see if I run into issues. I guess it's not a problem as long as it's working. A little perturbed though that it seems my chamber isn't what I thought it was.

 

[Alex Wheeler]

We use the .2 line just spec things out. The click comes from the brass that expands to fit the chamber just in front of the solid web. Different cases have different thickness of solid web. Some the .2 line is close to the problem area, others its up closer to .35-.4. The main thing is, measure the fattest part of your fired case, resize it and measure again. If its bringing it down .001 you will probably be fine in a .284. Not in a magnum though. A .284 is not capable of running very high pressures and the smaller case heads require less squeeze to work. No one size fits all. On a 284 Id spec my sizer .004 under at the base just like you did. You can expect a reamer to be a little over sized. They do it on purpose. There is a tolerance and they dont try to hit the low end. But it does sound like yours is a little fatter than the extra .0005 they allow.

 

[Tac-O]

We use the .2 line just spec things out. The click comes from the brass that expands to fit the chamber just in front of the solid web. Different cases have different thickness of solid web. Some the .2 line is close to the problem area, others its up closer to .35-.4. The main thing is, measure the fattest part of your fired case, resize it and measure again. If its bringing it down .001 you will probably be fine in a .284. Not in a magnum though. A .284 is not capable of running very high pressures and the smaller case heads require less squeeze to work. No one size fits all. On a 284 Id spec my sizer .004 under at the base just like you did. You can expect a reamer to be a little over sized. They do it on purpose. There is a tolerance and they dont try to hit the low end. But it does sound like yours is a little fatter than the extra .0005 they allow.

That is good to know. Thank you!

 

[garyatlp]

I recently purchased a supposedly new Bergara Ridgeback that I'm guessing is a few years old simply based on it having a .130 throat unless they're all chambered the same. The chamber neck is also tight as a bullet isn't loose in a fired case neck (which is why I went online to see what I could find out about it and found this thread which is the first I've heard of the resizing problem). I haven't been able to locate a print for the original .130 throat so I could compare chamber neck size between it and the saami specs. A pressure sign I'm having is case expansion above the extractor groove, .0015"-.002", I've always loaded to never have more than .0005" expansion here. Bolt lift is normal. I believe I'll end up buying a tool to turn the necks down and recheck case expansion. I'm using the Norma 143 gt loaded ammo because I found it cheaper than I could find brass for. Here's the specs for the Norma ammo if anyone is interested. It may be brass that has no sizing/bolt click problems. I've heard over the years it's softer so maybe less springback upon sizing.
Web = .529" Case length = 2.022" OAL = 2.845" (.133" jump in this Bergaras throat)
Neck thickness = .0145" Bullet diameter = .264" length = 1.455" Powder = 55.3 grains (MRP?)
Accuracy without the best gun rest was .7" and 1" 5 shot groups at 100yds.
I can check back in after a few reloads but that won't be for a few months.

 

[BrentM]

I recently purchased a supposedly new Bergara Ridgeback that I'm guessing is a few years old simply based on it having a .130 throat unless they're all chambered the same. The chamber neck is also tight as a bullet isn't loose in a fired case neck (which is why I went online to see what I could find out about it and found this thread which is the first I've heard of the resizing problem). I haven't been able to locate a print for the original .130 throat so I could compare chamber neck size between it and the saami specs. A pressure sign I'm having is case expansion above the extractor groove, .0015"-.002", I've always loaded to never have more than .0005" expansion here. Bolt lift is normal. I believe I'll end up buying a tool to turn the necks down and recheck case expansion. I'm using the Norma 143 gt loaded ammo because I found it cheaper than I could find brass for. Here's the specs for the Norma ammo if anyone is interested. It may be brass that has no sizing/bolt click problems. I've heard over the years it's softer so maybe less springback upon sizing.
Web = .529" Case length = 2.022" OAL = 2.845" (.133" jump in this Bergaras throat)
Neck thickness = .0145" Bullet diameter = .264" length = 1.455" Powder = 55.3 grains (MRP?)
Accuracy without the best gun rest was .7" and 1" 5 shot groups at 100yds.
I can check back in after a few reloads but that won't be for a few months.

Picture isn't all that clear but I sure don't see any significant pressure indicators. I also highly doubt the throat isn't saami cut. Your neck after firing measures what? I can see this brass springing back .001-.0015 and therefore not allowing a bullet to fall in the case. As far as the web, .5290 is pretty much spot on for virgin brass and my hornady brass doesn't expand past .530 even with 10 reloads. It seems like you are fine.

 

[garyatlp]

Picture isn't all that clear but I sure don't see any significant pressure indicators. I also highly doubt the throat isn't saami cut. Your neck after firing measures what? I can see this brass springing back .001-.0015 and therefore not allowing a bullet to fall in the case. As far as the web, .5290 is pretty much spot on for virgin brass and my hornady brass doesn't expand past .530 even with 10 reloads. It seems like you are fine.

Thanks for the response.
I had taken a shortcut in my low budget methodology for locating where the bullet hits the lands and I was wrong. Rechecked and OAL with a Hornady 147 is 2.990". That would be jammed into the rifling a little bit so bullet is contacting rifling at a slightly shorter length. So it seems the throat is longer than I initially thought. After further neck measurements I concluded I have at least .004" clearance, I found once I pushed a bullet into a fired case past the mouth of the neck it was then loose, the mouth of the neck was springing back more than the rest. I found an 6.5 PRC article from 2019 in Rifle Shooter Magazine by John Barsness "Bullets should fit easily into fired necks, but some revealed a little tightness right at the mouth of the case, indicating the case mouths had probably been "crimped" slightly by the front end of the chamber....Trimming the tight case mouths slightly allowed all five bullets to slip easily into the necks. Experimentation eventually revealed a trim length of 2.010 inches solved the problem". Don't know yet if this is the same as my issue.
However the expansion at the web is still .002". So unfired is .529 and after firing is .531 (accuracy of the actual reading is only .001" however the .002" difference before fired and new is spot on). Pulled bullets and reseated .110" longer which moved boattail juncture from shoulder area to base of neck, should have dropped pressure some but web expansion is unchanged. Generally with my reloads if Im getting .0005" expansion here I'm thinking the load is close to 60,000 psi . Just starting out with this cartridge so time will tell. I should have researched the cartidge more. Who would expect a factory cartidge to have issues with chamber/brass/die compatibility?
Attached a picture of the 143 gt compared to 147 eldm, Norma has a hunting bullet, 143 Bondstrike with a .629 bc but I know nothing about suitibility for long range.

 

[Randy Tidwell]

Hello Alex,

I have been following this blog on for awhile, allot of great info by you and others.

In 2021 I had two Ruger No1s built, 6.5 PRC and 300 Rum by Oregon Gun Smithing in Pendleton WA. Love them both; they did a wonderful job on both rifles. The problem I am having has nothing to do with their workmanship.

I am having extraction problems with both (ADG Brass) using below max loads, no pressure signs! The extraction issue is the worst with the Rum to the point I ended up bending the extractor. I know the No1s aren't known for a strong extraction system. It is at a custom gunsmiths locally to have the extractor replaced. So I can't do any detailed measurements at this time on the Rum as all my brass is with the smith.

I did some measuring on the brass for the PRC this morning, measured .200" up the web, 10 different cases measured .5322 to .5325. This rifle was chambered with a reamer I had made by Pacific tool with a .295 neck.

In comparing my reamer specs to your 6.5 PRC AW 2 drawing, we are .002 apart at the web. Do you think opening up my chamber that .002" might cure my problem? I'm also second guessing the tight neck; it was strictly my anal bench rest mindset that was over thinking the project, lol
I have ordered some pin gauges to confirm actual ID of the chamber.

Would your custom rifle department be able to run your reamer into these rifles for me?

Randy Tidwell

 

[capod28]

Similar experience here w/ Bergara 300 prc & Hornady. With medium loading, I've got 20 that had been loaded 7 times without issue. Still firm hold on primer also.

What dies are you using?

 

[wasskeet]

What dies are you using?

The plain-Jane Hornady FL non-bushing die set.

 

[capod28]

The plain-Jane Hornady FL non-bushing die set.

Thx. Have a Bergara, too, and just loaded some ADG. Anxious to see how they do. If we're lucky, maybe the Bergara chambers are made a little loose. Use Redding FL bushing.