This is a weird reloading situation ...

[rustyinbend]

I've been fire-forming a bunch of new 300-PRC Lapua brass. Took some 1x fired brass out for a test spin yesterday and they wouldn't fit into the chamber ... bolt wouldn't close on any of them at the range. Brought 'em home and because it's an MRAD and super easy ... I pulled the barrel and sure enough, the rounds wouldn't seat into the chamber. Went to my sized 1x fired brass that I used for this, and they fit just fine. Dismantled the ammo and re-sized and that made the cases fit just fine ... dropped in and dropped out easily.

Charged and seated the bullets and checked again ... No-Go. Scratched my head over that one, and figured maybe I'd screwed up the head space and the bullets were hitting the lands. Went through that whole process again and it all checked good. Decided to take one of the finished cartridges that didn't fit, and decrease seating depth steadily until it dropped in the chamber ... No-Go. So the problem is not about the bullet hitting the lands, or the size of the case at the beginning of the seating process.

Pulled the bullet to test the case ... and it didn't fit. I'm stumped. How the heck does seating the bullet take a perfectly good case that fits fine, and turn it into a case that doesn't fit in the chamber. What am I missing here? I'm not even sure about next steps to troubleshoot this ...

 

[CoryT]

Tight neck? Measure neck diameter vs ones that fit, you may need to neck ream or outside turn.

 

[roostercogburn98]

Maybe bulging round the case mouth. Make sure you seated good and straight

 

[Huskydriver]

I've been fire-forming a bunch of new 300-PRC Lapua brass. Took some 1x fired brass out for a test spin yesterday and they wouldn't fit into the chamber ... bolt wouldn't close on any of them at the range. Brought 'em home and because it's an MRAD and super easy ... I pulled the barrel and sure enough, the rounds wouldn't seat into the chamber. Went to my sized 1x fired brass that I used for this, and they fit just fine. Dismantled the ammo and re-sized and that made the cases fit just fine ... dropped in and dropped out easily.

Charged and seated the bullets and checked again ... No-Go. Scratched my head over that one, and figured maybe I'd screwed up the head space and the bullets were hitting the lands. Went through that whole process again and it all checked good. Decided to take one of the finished cartridges that didn't fit, and decrease seating depth steadily until it dropped in the chamber ... No-Go. So the problem is not about the bullet hitting the lands, or the size of the case at the beginning of the seating process.

Pulled the bullet to test the case ... and it didn't fit. I'm stumped. How the heck does seating the bullet take a perfectly good case that fits fine, and turn it into a case that doesn't fit in the chamber. What am I missing here? I'm not even sure about next steps to troubleshoot this ...

On an empty case that doesn't fit, where is it getting stuck on the case? near the web?

 

[918v]

If your seater die is set to low it could be crimping the case mouth and collapsing the shoulder which causes the body diameter to expand.

 

[Steel head]

If your seater die is set to low it could be crimping the case mouth and collapsing the shoulder which causes the body diameter to expand.

I learned that lesson years ago.

 

[rustyinbend]

So all these suggestions got me thinking about stress-testing the size and specs of brass that doesn't work after seating. Long story short ... I figured out that the very end of the case mouth was at, or slightly over the max spec of .3410 ... on a very slight "bulge". It's less on sized and unseated brass, but when seating a bullet, it expands just enough to be out of spec. So even though the COAL is at a size that doesn't "require" trimming, I went ahead and trimmed down to trim-length (2.565) and ... VOILA ... case drops in and out of the chamber.

Then I seated a bullet and ... VOILA x 2 ... it seats in the chamber just fine. Apparently I need to trim this slight bulge at the top of the case mouth on all my brass, whether or not it needs trimming for COAL specs ... to make this problem go away.

Thanks for everyone's advice. Time to do some trimming and try all this again.

 

[hafejd30]

What sizing and seater did are you using? Backing your seater off a bit may cause the case not to bulge. Typically I can go several firings on my cases before I need to trim. Haven’t played with the 300 PRC Lapua yet tho

 

[rustyinbend]

What sizing and seater did are you using? Backing your seater off a bit may cause the case not to bulge. Typically I can go several firings on my cases before I need to trim. Haven’t played with the 300 PRC Lapua yet tho

I use the Redding Competition Micrometer Seating Die ... very high end. Set up per the instructions to screw down until it just touches the ram, and then back off to set the micrometer guide facing forward. Do you think I should back off more than that?

 

[rustyinbend]

Oh ... and the Redding Type-S Bushing FL Sizing Die.

 

[kyzim311]

I use the Redding Competition Micrometer Seating Die ... very high end. Set up per the instructions to screw down until it just touches the ram, and then back off to set the micrometer guide facing forward. Do you think I should back off more than that?

screw down until what touches the ram (die body or sleeve)? You should still be compressing the floating sleeve if setup right.

 

[rustyinbend]

What sizing and seater did are you using? Backing your seater off a bit may cause the case not to bulge. Typically I can go several firings on my cases before I need to trim. Haven’t played with the 300 PRC Lapua yet tho

BTW ... in order to get the shoulder bump correct, I have to cam-over just a bit and use a .002 shell holder. If I back off on either of those, I can't get the proper shoulder bump.

 

[rustyinbend]

screw down until what touches the ram (die body or sleeve)? You should still be compressing the floating sleeve if setup right.

Exactly what I do.

 

[918v]

I stopped using bushing dies because they turn the necks into funnels. This is fine if you crimp into a canelure afterwards but not so good if you have a tight chamber.

Glad you figured it out. If I were you I would neck size with a a LCND before you body size or just use a LCND to deprime. That way the case mouth will always be the same diameter as the rest of the neck.

 

[rustyinbend]

I stopped using bushing dies because they turn the necks into funnels. This is fine if you crimp into a canelure afterwards but not so good if you have a tight chamber.

Glad you figured it out. If I were you I would neck size with a a LCND before you body size or just use a LCND to deprime. That way the case mouth will always be the same diameter as the rest of the neck.

Interesting ... I use the bushing die to size-down the neck, and then before charging I run my cases through my 21st Century Mandrel to size the neck to exactly where I want it. Started with the combo deprimer/neck-sizer and never warmed up to it. For some reason, this 300-PRC kicked my butt until I solved this ... haven't had any issues in my other handloading calibers.

 

[hafejd30]

Interesting ... I use the bushing die to size-down the neck, and then before charging I run my cases through my 21st Century Mandrel to size the neck to exactly where I want it. Started with the combo deprimer/neck-sizer and never warmed up to it. For some reason, this 300-PRC kicked my butt until I solved this ... haven't had any issues in my other handloading calibers.

If you figure it out please update this thread. I will be running the exact dies/mandrel/Lapua brass that you are when I get my components. So the information would be appreciated

 

[rustyinbend]

If you figure it out please update this thread. I will be running the exact dies/mandrel/Lapua brass that you are when I get my components. So the information would be appreciated

Solved above ... short version ... sizing process delivered a slightly over-spec diameter at the very top of the case mouth that didn't show until the bullet insertion expanded the neck. All solved with a little trimming. Details in my post above.

 

[Feniks Technologies]

I use the Redding Competition Micrometer Seating Die ... very high end. Set up per the instructions to screw down until it just touches the ram, and then back off to set the micrometer guide facing forward. Do you think I should back off more than that?

How much did you have to trim off the length?

Most every time I’ve seen issues with case mouth flaring, it’s a seating die screwed too far down.

 

[rustyinbend]

How much did you have to trim off the length?

Most every time I’ve seen issues with case mouth flaring, it’s a seating die screwed too far down.

Just a little trimmed, just enough to lose the flare at the very end. I'll back off the die one more rotation and see if that helps. Thanks.

 

[918v]

How much did you have to trim off the length?

Most every time I’ve seen issues with case mouth flaring, it’s a seating die screwed too far down.

When you screw a seater die too far down it crimps the case mouth, not flares it.

 

[Feniks Technologies]

When you screw a seater die too far down it crimps the case mouth, not flares it.

I could obviously be wrong, but this looks flared. I’ve seen different dies do weird things when not setup up properly.

 

[918v]

I could obviously be wrong, but this looks flared. I’ve seen different dies do weird things when not setup up properly.

Did you do that with a Redding Competition Seater?

 

[Huskydriver]

Did you do that with a Redding Competition Seater?

Pro tip: rumor has it you are potentially arguing with a mod just a friendly heads up if u didn't know so you don't get banned lol. I have never seen a seater flare a case mouth either but have seen it buckle shoulders and roll the case mouth inward like crimping.

Rusty....it's cuz you shoot an mrad instead of an AI... allegedly.... Probably... Maybe

 

[Feniks Technologies]

Pro tip: rumor has it you are potentially arguing with a mod just a friendly heads up if u didn't know so you don't get banned lol. I have never seen a seater flare a case mouth either but have seen it buckle shoulders and roll the case mouth inward like crimping.

Rusty....it's cuz you shoot an mrad instead of an AI... allegedly.... Probably... Maybe

No one being banned. Lol

I believe that was a Redding. Can’t remember.

 

[Feniks Technologies]

Did you do that with a Redding Competition Seater?

I believe it was.

 

[918v]

Just a little trimmed, just enough to lose the flare at the very end. I'll back off the die one more rotation and see if that helps. Thanks.

Screw down the seater body to touch the shell holder. Make sure the sliding sleeve can be flush with the die body. Then put a case in it and raise the ram feeling for the case mouth bottoming out in the sleeve. It should not. There should be plenty of clearance in there. If the case mouth bottoms out you will see light between the shell holder and the die.

 

[Yondering]

When you screw a seater die too far down it crimps the case mouth, not flares it.

Except that more than a little crimp can turn into a bulge while also shoving a burr up around the od of the case mouth, which some people might interpret as a flare.

 

[Choid]

You just want the sleeve to capture and hold the case. You don't need to screw it down to the shellholder, one or two turns after it starts to compress is plenty.

 

[918v]

Except that more than a little crimp can turn into a bulge while also shoving a burr up around the od of the case mouth, which some people might interpret as a flare.

I don’t think so.

 

[918v]

You just want the sleeve to capture and hold the case. You don't need to screw it down to the shellholder, one or two turns after it starts to compress is plenty.

You do if you want to enjoy the complete range of the micrometer.

 

[Yondering]

You just want the sleeve to capture and hold the case. You don't need to screw it down to the shellholder, one or two turns after it starts to compress is plenty.

Incorrect. While you can set up the die that way and it will seat bullets, it misses most of the point of using that type of die.

The purpose of the sliding stem is to support the case AND bullet together from start to finish during seating; adjusting as you describe only does that during the last small bit of seating, which is of little value.

 

[Yondering]

I don’t think so.

Sure, if you’ve never seen it. Personally I have, so I don’t need to “think so” or not because it’s fact.

 

[Fighting the good fight]

I've been fire-forming a bunch of new 300-PRC Lapua brass. Took some 1x fired brass out for a test spin yesterday and they wouldn't fit into the chamber ... bolt wouldn't close on any of them at the range. Brought 'em home and because it's an MRAD and super easy ... I pulled the barrel and sure enough, the rounds wouldn't seat into the chamber. Went to my sized 1x fired brass that I used for this, and they fit just fine. Dismantled the ammo and re-sized and that made the cases fit just fine ... dropped in and dropped out easily.

Charged and seated the bullets and checked again ... No-Go. Scratched my head over that one, and figured maybe I'd screwed up the head space and the bullets were hitting the lands. Went through that whole process again and it all checked good. Decided to take one of the finished cartridges that didn't fit, and decrease seating depth steadily until it dropped in the chamber ... No-Go. So the problem is not about the bullet hitting the lands, or the size of the case at the beginning of the seating process.

Pulled the bullet to test the case ... and it didn't fit. I'm stumped. How the heck does seating the bullet take a perfectly good case that fits fine, and turn it into a case that doesn't fit in the chamber. What am I missing here? I'm not even sure about next steps to troubleshoot this ...

Case bulge possibly is it a compressed charge or over crimped and slightly bulged the case. Something is not concentric or true.

 

[918v]

Sure, if you’ve never seen it. Personally I have, so I don’t need to “think so” or not because it’s fact.

Maybe you should go to school and learn English then because a fucked up crimp does not resemble a flare.

 

[Yondering]

Maybe you should go to school and learn English then because a fucked up crimp does not resemble a flare.

Maybe you should read more carefully and stop thinking your imagination counts for everything.

 

[Choid]

Incorrect. While you can set up the die that way and it will seat bullets, it misses most of the point of using that type of die.

The purpose of the sliding stem is to support the case AND bullet together from start to finish during seating; adjusting as you describe only does that during the last small bit of seating, which is of little value.

Well, that is what John Whidden says in his setup video, so I am OK with that.

 

[Namekagon]

I don't think I'd be content to think that trimming fixed this problem. The case mouths should not be getting flared. Need to find root cause, which likely resides in either the mandrel or the seating die.

 

[Fighting the good fight]

if your seating and getting a bulge at the bottom of the neck its being over crimped. But im confused cause someone is saying flaired that should only happen if your sizing long brass or not setting your die correctly. Just my 2 cents

 

[Tnc]

Any chance you clean brass by stainless tumbling? I had some used brass from a guy who did and all the case mouths were peened over and looked very similar to yours. I had to trim the shit out of them to get rid of it.

 

[NORCAL50]

Buddy of mine didn't realize he had a match chamber. Turned the necks and now his rounds chamber just fine.

 

[rustyinbend]

So I did a few things ...

(1) Reset my FL sizing die to ensure proper should bump (-4/1,000)
(2) Trimmed cases to published trim length
(3) Reverify COAL to fit easily in the chamber
(4) Put a slight crimp on the case mouth
(5) Took the buffer and spring back to stock parts (removed the JP-SCS setup)
(6) Load with a lighter charge to eliminate pressure possibilities as root cause

After doing these things, my loaded cartridges dropped easily in and out of the barrel/chamber.

Now that I "know" that everything "should" work ... I'm headed to the range today to see if it "does" work. If OK, declare victory. If not OK, then the rifle goes back to LWRCI to figure out what's wrong.

 

[Huskydriver]

So I did a few things ...

(1) Reset my FL sizing die to ensure proper should bump (-4/1,000)
(2) Trimmed cases to published trim length
(3) Reverify COAL to fit easily in the chamber
(4) Put a slight crimp on the case mouth
(5) Took the buffer and spring back to stock parts (removed the JP-SCS setup)
(6) Load with a lighter charge to eliminate pressure possibilities as root cause

After doing these things, my loaded cartridges dropped easily in and out of the barrel/chamber.

Now that I "know" that everything "should" work ... I'm headed to the range today to see if it "does" work. If OK, declare victory. If not OK, then the rifle goes back to LWRCI to figure out what's wrong.

Why are you crimping precision rifle loads?

 

[rustyinbend]

Why are you crimping precision rifle loads?

It's a 6.5-CM AR10 (LWRCI REPR MKII Elite) and I wanted to take "recoil" out of the equation. It's a very light crimp ... just a 1/4 turn at the end of the seating range.

 

[Huskydriver]

It's a 6.5-CM AR10 (LWRCI REPR MKII Elite) and I wanted to take "recoil" out of the equation. It's a very light crimp ... just a 1/4 turn at the end of the seating range.

Oh thought this was your 300prc barrel on your mrad....still though I prefer just using more neck tension rather than crimping for semi auto loads

 

[rustyinbend]

Oh thought this was your 300prc barrel on your mrad....still though I prefer just using more neck tension rather than crimping for semi auto loads

You're right ... I was getting two different current "issues" conflagrated. Sorry. Same basic fix for the 300-PRC, but without the crimp. Post load, the cartridge fits perfectly in the chamber so I'm hopeful this is solved ... for both rifles. Will report back later today.

 

[rustyinbend]

UPDATE ...

So there I was at the range, with a perfect and almost impossible December weather day in Central Oregon ... 60-ish, sunny, and virtually no wind. The Sight-In Range at COSSA was deserted with only one other guy shooting about 20 benches away. As I hung my targets, I thought to myself: "This is the day all of my 300-PRC issues will be resolved, and my handloads will be perfect". I set up my bench, positioned my Labradar, and burrowed in to test the 20 rounds I'd meticulously built and dry-tested for chamber sizing. I fired my usual factory cold-barrel cartridge (Hornady 225gr ELDM) and it went straight through the 100-yard bullseye. I loaded the first five handload cartridges into my Barrett MRAD magazine, seated the magazine, threw the bolt home with the round seating flawlessly (Woohoo ... this was, after all, the issue I was trying to solve), and armed the Labradar. Sighted in, squeeze the bag, breath ... hold ... and squeeeeeeze the trigger.

"CLICK" ... nothing ... nadda ... squat-o-lah ... the big bupkiss !!!

I pulled back the bolt thinking I must not have picked up a cartridge, maybe didn't fully seat the magazine. But to my surprise, out popped a loaded cartridge. I picked it up off the ground and it had what appeared to be a perfect primer strike. Thinking maybe the first round had a defect, I loaded a second round ...

"CLICK" ... again.

At that point, I stopped, audibly said "WTF" (loud enough for the guy 20 benches away to say "You talkin' to me?") ... and decided to wait till I got home to figure it out. The trip wasn't a total loss though since I had a 6.5 AR10 test go well, and I swapped the 300-PRC MRAD barrel for a 338-Lapua barrel and advanced my load development work on that with a very successful ladder test. The whole easy 5-minute barrel swap MRAD thing is amazing ... by the way.

Got home, pulled the bullet off of the non-firing round ... and it was ... ugh ... "EMPTY". NO POWDER. Same story for the other 19 cartridges.

I remembered that while I was building those cartridges, my wife asked me to help her with some meaningless and innocuous house "thing" ... so I TOTALLY blame my wife for this oversight, and told her she can NEVER again talk to me while I'm in my reloading room. Just like a woman ... she laughed at me and refused to accept responsibility, even though this was clearly her fault. Oh well, she's a good cook, and I do have 43 years invested in the relationship, so I didn't force her to move out (for this first offense).

I carefully neck-resized, remandrelled, primed the two rounds I'd attempted to shoot, and built back to 20 perfect cartridges that are now ready to shoot. I even included powder this time.

Go ahead ... tell me you've never forgotten powder and make me feel even stupider than I already do. Go ahead ... I DARE YOU !!!

 

[hafejd30]

I load one round per time from powder charge to seating bullet. Visually confirming each case on the swap

I’m surprised the primer didn’t have enough to send the bullet into the barrel

 

[OREGUN]

Yeah…prime them all and then charge and seat one at a time to completion is my method too.

Perfect days at the range can always be spoiled by some bullshit…left the ammo at home, left the chrony at home, a super enthusiastic Fudd shows up and wants to talk all day with his new best buddy, timing belt breaks on the drive in, unexpected closure for a pistol match that was clearly on the calendar that you forgot to check, tie rod end breaks on the way home…just a few of my personal favorites.

PS: I replaced that pickup.

 

[rustyinbend]

I load one round per time from powder charge to seating bullet. Visually confirming each case on the swap

I’m surprised the primer didn’t have enough to send the bullet into the barrel

I'm a "batch guy" ... and have never had an issue (until now). I prime the batch. Charge the batch. And then seat the batch. Maybe need to re-think that, given what just happened.

 

[nn8734]

It happens to everyone at some point.

Happened to me once and since then, for every charged batch, i run a flash light over all the cases before seating. Cant tell you how many empties i caught since then but its a lot.