Saving brass/loose primer pockets

[trilogymac]

OK, I've seen the Hart tool and heard of people using the RCBS swagger to "tighten" pockets neither of which seemed like a good solution to me. So, in an attempt to make a better mouse trap, my buddy and I took a .308 small base die and cut the top off of it right below where the body meets the shoulder. I measured a few new FGMM loaded ammo at the base and came up with a dimension of .465. We measured the ID of the SB die and found that .463 was at a point .500 up from the bottom. We were looking for .463 to compensate for spring back. I bored the die from the top, down to a point .500 up from the die bottom. We bored to a diameter of .480. You can use whatever you like as it is only clearance. Then we made a "pusher", 3/8 diameter x 1-1/4" long from an old cobalt end mill shank. We went over to the small hydraulic press that we have in the shop and placed the die upside down on 2 bars that would allow the case to fall thru after being pressed completely thru the die. The case was lubed and placed upside down in the die which was also upside down. We pushed the case all the way thru the die until it popped out of the bottom.

Just as anticipated, the case measured .465 after swagging, and the primer pockets are tight again. We swagged 10 cases that the primers would literally fall out of, and they felt like they were being inserted into new brass again.

This was just a rough first test that I'm sure can be refined, but it appears to work well. so, if you have access to a lathe and want to save brass with large pockets, you may want to give it a try!

Oh, a Rockchucker doesn't have enough ass to push the case thru so you need something like a small hyd press.

Hope this helps!!

Best,
Trilogymac

 

[TenZero]

This sounds similar in theory to the Redding GRX dies that take the Glock Bulge out of pistol brass. Does it really tighten up the primer pockets, or just squeeze the case head dimension down?

 

[mscott]

You might be onto something there. Better talk to somebody before someone else makes a bunch of $$ on your idea.

 

[Turd in the Pool]

Better yet, back off of your load.

 

[trilogymac]

This sounds similar in theory to the Redding GRX dies that take the Glock Bulge out of pistol brass. Does it really tighten up the primer pockets, or just squeeze the case head dimension down?

I'd never seen that Redding die but yes that' s the way it works. Shrinks the case head and tightens the pocket.

 

[two4spooky]

Just as anticipated, the case measured .465 after swagging, and the primer pockets are tight again. We swagged 10 cases that the primers would literally fall out of, and they felt like they were being inserted into new brass again.

You should offer this service, for a reasonable fee of course, to the members here. You might get a few takers.

 

[Turd in the Pool]

I see a bunch of case head separation in someone's future!

 

[TenZero]

I'd never seen that Redding die but yes that' s the way it works. Shrinks the case head and tightens the pocket.

Very cool. I use my GRX dies constantly, but I never would have thought of this. Only other concern is how worn out are all the other parts of the case, by the time the primer pockets are blown out? Might be good to use em as throw downs in a lost brass match.

 

[trilogymac]

Tenzero,

The brass I fixed only has a couple of firings on them. It is a bag I've accumulated over years of ladder testing.
Your right, don't put them back in with your main brass pool. I'm going to shoot UKD plates out in the field with it in my semis so if I loose it in the grass or whatever, I'm not getting wrapped around the axle. Allot of it is FGMM and we know who soft that is

RJB has a good point about head separation. Probably will do the inside "hook" test and bore scope it just for fun.

 

[bcrich]

Better yet, back off of your load.

Or try Tula primers which are a cunt hair bigger and seat really snug, good thinking though MCGyver!

 

[RampedRaptor]

Awesome idea. I wonder how well the new sized pockets will last after 1....or 10 firings?

Great job!

 

[JWV]

I think FTR shooters would love this. I was talking to some of them at the last match I shot and they said they get about 3 loadings out of Lapua 308 with 215gr bergers. They load those things to the ragged edge! Dasher shooters may also love this!

 

[ranger1183]

OK, I've seen the Hart tool and heard of people using the RCBS swagger to "tighten" pockets neither of which seemed like a good solution to me. So, in an attempt to make a better mouse trap, my buddy and I took a .308 small base die and cut the top off of it right below where the body meets the shoulder. I measured a few new FGMM loaded ammo at the base and came up with a dimension of .465. We measured the ID of the SB die and found that .463 was at a point .500 up from the bottom. We were looking for .463 to compensate for spring back. I bored the die from the top, down to a point .500 up from the die bottom. We bored to a diameter of .480. You can use whatever you like as it is only clearance. Then we made a "pusher", 3/8 diameter x 1-1/4" long from an old cobalt end mill shank. We went over to the small hydraulic press that we have in the shop and placed the die upside down on 2 bars that would allow the case to fall thru after being pressed completely thru the die. The case was lubed and placed upside down in the die which was also upside down. We pushed the case all the way thru the die until it popped out of the bottom.

Just as anticipated, the case measured .465 after swagging, and the primer pockets are tight again. We swagged 10 cases that the primers would literally fall out of, and they felt like they were being inserted into new brass again.

This was just a rough first test that I'm sure can be refined, but it appears to work well. so, if you have access to a lathe and want to save brass with large pockets, you may want to give it a try!

Oh, a Rockchucker doesn't have enough ass to push the case thru so you need something like a small hyd press.

Hope this helps!!

Best,
Trilogymac

This is a great post! Would like to see step-by-step pictures or video of how you did this.

 

[Deadshot2]

Just out of curiosity, what happens to the other dimension in the primer pocket? Does it alter the depth any?

Have you checked the diameter reduction for uniformity by running a swaging punch into the pocket?

This sure sounds like it has merit. What would you estimate the minimum "tonnage" of the press required to do this job? Might be possible to use a heavy duty arbor press similar to that used in a lot of shops for removing or installing shaft bearings.

 

[wilecoyote]

rcbs AMMOMASTER has the necessary strenght & leverage to "push the case thru"_
I presume that, after this passage, the shoulder height will be grown, therefore mandatorily measured and re-lowered to the correct specs.

to Deadshot2: bearing presses as you mentioned will do, for sure_
(I've AMMOMASTER and a little bearing pr_ tested both on use exactly like this,even if not p./pocket reduction oriented_ both works w/o any effort_

 

[trilogymac]

Wile,
That is an interesting question about the shoulder. I hadn't gotten that far yet. I was just thrilled that the pocket tightened up
My tool looks very much like the Redding GSX. I did a full length resize before running them thru the SB modified die to keep the pressure needed to push it all the way thru to a minimum. It may need to be run back thru the FL sizer. I'll check later this afternoon. Not sure about pocket depth yet either, another good question but when I pushed the primer in, the depth looked/felt right.

There are numerous obvious improvements that could be done to the setup like a punch holder that mounts to the ram, some sort of basket (besides my hand) under the die to catch the brass etc.

Hope this helps!

 

[wilecoyote]

Wile,
... It may need to be run back thru the FL sizer...

...this, but if aside some minor improvement, your task is effective, your name will be forever written in the sky_

 

[trilogymac]

I had a chance to do a little bit of evaluation of the swage process. Swaged 4 and checked a few dimensions.
The brass was Winchester and had 5 firings.

Primer pocket depth uchanged
extractor groove reduction (blade Micrometer) .0007-.0013
OD reduction (OD micrometer) .003-.004
primer pocket reduction (pin gages) .003

I checked the inside of the cases with a hook and bore scope and found no sign of impending case separation.

So far so good!
Trilogymac

 

[ranger1183]

I think this is worth repeating. Would like to see step-by-step pictures -or- video of your setup and how you do this re-sizing. The implications of extending brass life because loose primer pockets is no longer an issue is a game changer for reloaders.

 

[Petrov]

I love this place!

 

[coues7]

This is a great idea