6.5 PRC shoulder crushing issues

[Lawnboi]

What’s the inside brass dimension before you try to seat the bullet?

I’d contact Peterson, or try a different lot or brand at this point

 

[Laelkhunter]

I would try a little more chamfer on the inside of the case mouth. However much you are chamfering, I would do a little more. Just do one case and see if it helps.

 

[JF_Idaho]

That neck looks crimped in the picture

 

[coast range]

Yeah I did that to one piece of adg in 6.5. It did not look that bad though. My id was .260 so I ran my LCD through some and that worked then I tried just using graphite on the bullet and that worked so I just loaded them up. I know you have already gone above and beyond that. I’d contact Peterson and see what they have to say

 

[Schmo]

What’s the inside brass dimension before you try to seat the bullet?

I’d contact Peterson, or try a different lot or brand at this point

Right at .260”. That’s after running it over a .263 expander button too.

 

[TaperPin]

Here’s a pic of the issue. I did what Lawnboi suggested. Lubed inside the neck, then ran it over a mandrel, then dry tumbled with polish for awhile. My mandrel is a .262”, not a .264” like I thought. What size of mandrel should I go to?

View attachment 877009

Your mandrel is fine. Even with twice or three times that much neck tension the boat tail would just expand the neck as it seats.

It really looks like it’s being crimped at the case mouth. That’s a good thing since it’s an easy fix.



Just to refresh memory of how a regular RCBS seating die is adjusted, with the seating die backed way way off or even out, first run an empty case (without bullet) all the way up without any resistance from contacting the case. Then carefully screw the die down until you feel the crimper just contact the case neck and back the die off a half to full turn and set the lock ring. Then adjust seating depth.

 

[Schmo]

Your mandrel is fine. Even with twice or three times that much neck tension the boat tail would just expand the neck as it seats.

It really looks like it’s being crimped at the case mouth. That’s a good thing since it’s an easy fix.

View attachment 877084

Just to refresh memory of how a regular RCBS seating die is adjusted, with the seating die backed way way off or even out, first run an empty case (without bullet) all the way up without any resistance from contacting the case. Then carefully screw the die down until you feel the crimper just contact the case neck and back the die off a half to full turn and set the lock ring. Then adjust seating depth.

My question regarding it looking like it’s crimped. The case mouth is nowhere close to the crimper when the shoulder crush happens. Like I said, the crush happens very early in the stroke in the seating process. Basically no part of the shank of the bullet gets in the neck.

 

[JGRaider]

The Redding Neck Die, Series B, 81487 will solve your problem no matter what brand of brass you're using. I'll even send it to you on my dime for you to see for yourself if you'd like.

 

[TaperPin]

My question regarding it looking like it’s crimped. The case mouth is nowhere close to the crimper when the shoulder crush happens. Like I said, the crush happens very early in the stroke in the seating process. Basically no part of the shank of the bullet gets in the neck.

If you can run a case without bullet all the way up into the seating die and the crimper doesn’t make contact, then it’s bad batch of brass, either it’s way thinner than normal, or softer.

 

[mthunter1989]

@Schmo what's the lot number on your brass? I've got a fresh box of Peterson 6.5 PRC for when I get my barrel spun on. I can check and see if there is an issue loading them this weekend, whether its the same lot or not.

 

[Lawnboi]

Right at .260”. That’s after running it over a .263 expander button too.

I’m guessing if you sized it you squeezed the neck with Peterson, it’s normally pretty thick. Spring back is a thing and sometimes when you squeeE it that hard it dosnt expand to what your button is.

Are you 100% sure this is not a die problem?

 

[Schmo]

I’m guessing if you sized it you squeezed the neck with Peterson, it’s normally pretty thick. Spring back is a thing and sometimes when you squeeE it that hard it dosnt expand to what your button is.

Are you 100% sure this is not a die problem?

Right, it’s not a die problem. I’ve tried it with chamfered/deburred virgin brass, virgin brass run through the FL die, and even once fired/resized that was fired by my buddy that I bought the brass from. All three do it. The necks are just too tight, so it’s gonna require a bigger mandrel. I ordered one tonight. Also, I just did an experiment. With the shoulder crushing, that has been with 147 ELD-Ms. The case mouth is hitting right at the heel of the bullet when the seating pressure starts. As an experiment, I loaded a 147 backwards in an empty case, just to see how it seated. It seated flawlessly, because of the tapering ogive profile. So mouths are just too much undersized. Seems like I can fix this with the appropriate mandrel size. Do you agree?

It still seems dumb that the FL die expander button is too much undersized. After I get a firing on all this brass, I think the problem will be solved. I have some 6.5 PRC bushing dies on order for another rifle, and will probably use those to load for this one too. An appropriate bushing size should keep this from happening on subsequent firings.

 

[Lawnboi]

Right, it’s not a die problem. I’ve tried it with chamfered/deburred virgin brass, virgin brass run through the FL die, and even once fired/resized that was fired by my buddy that I bought the brass from. All three do it. The necks are just too tight, so it’s gonna require a bigger mandrel. I ordered one tonight. Also, I just did an experiment. With the shoulder crushing, that has been with 147 ELD-Ms. The case mouth is hitting right at the heel of the bullet when the seating pressure starts. As an experiment, I loaded a 147 backwards in an empty case, just to see how it seated. It seated flawlessly, because of the tapering ogive profile. So mouths are just too much undersized. Seems like I can fix this with the appropriate mandrel size. Do you agree?

It still seems dumb that the FL die expander button is too much undersized. After I get a firing on all this brass, I think the problem will be solved. I have some 6.5 PRC bushing dies on order for another rifle, and will probably use those to load for this one too. An appropriate bushing size should keep this from happening on subsequent firings.

Still kind of strange. A bigger mandrel may help, I’d not even put it through a fl sizer if virgin, mandrel only, tumble and chamfer. This is fairly standard practice for me especially with tighter lapua or Peterson.

I keep a set of .001 under mandrels around for the very purpose of this.

I would also assess how your seated is contacting the bullet, I don’t see how your crushing shoulders in an uneven manner while it’s in seating die, make sure the stem is not making contact with the tip.

 

[Schmo]

@Lawnboi,
I really feel like an idiot now. I had my seating stem backed out as far as it would go, so I could bring it down as needed. I reset my die, and brought the seating stem down, and boom, it seats like a champ. Yes, I am a moron. Something with the die wasn’t set properly. It was my setup the whole time, not the brass. I’ll go back in my hole now.

 

[Odd1out]

@Lawnboi,
I really feel like an idiot now. I had my seating stem backed out as far as it would go, so I could bring it down as needed. I reset my die, and brought the seating stem down, and boom, it seats like a champ. Yes, I am a moron. Something with the die wasn’t set properly. It was my setup the whole time, not the brass. I’ll go back in my hole now.

Good on yea for admitting the mistake.

Sent from my SM-G986W using Tapatalk

 

[Lawnboi]

@Lawnboi,
I really feel like an idiot now. I had my seating stem backed out as far as it would go, so I could bring it down as needed. I reset my die, and brought the seating stem down, and boom, it seats like a champ. Yes, I am a moron. Something with the die wasn’t set properly. It was my setup the whole time, not the brass. I’ll go back in my hole now.

Mistakes happen and if there’s a time to make them it’s before things go boom.

 

[coast range]

Hell yeah who cares. PSA

Glad you figured it out. Can’t be the only person to ever do it, nor the last

 

[pbroski]

Your mandrel is fine. Even with twice or three times that much neck tension the boat tail would just expand the neck as it seats.

It really looks like it’s being crimped at the case mouth. That’s a good thing since it’s an easy fix.

View attachment 877084

Just to refresh memory of how a regular RCBS seating die is adjusted, with the seating die backed way way off or even out, first run an empty case (without bullet) all the way up without any resistance from contacting the case. Then carefully screw the die down until you feel the crimper just contact the case neck and back the die off a half to full turn and set the lock ring. Then adjust seating depth.

TaperPin for the win.