300 WM Question

DCAN

Sergeant of the Hide
Full Member
Minuteman
Aug 30, 2020
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I'm sure that I have overlooked something here, but I can't figure it out. Here is my issue:
Loading ADG brass that is new. Ran it through a neck sizing mandrel to be sure necks were round and sized for 2 thou neck tension. Primed, poured powder and started seating Hornady ELD-X bullets. Seating pressure required felt a bit high. Checked neck tension and it was right at 2 thou. 2-3 more rounds loaded and the seating die, a Forster Comp., started sticking. The die chamber was stuck in the compressed position.
Disassembled the whole thing and found the base of the seater stem had belled out and gouged the inside of the die chamber. I polished everything up and reassembled. Tried the whole process again. Same results as first time. Same hard seating pressure, same sticking, same belled out stem. Also noticed the case necks were showing marks from rough die chamber and a slight ring at the base of the neck.
The pic is of the rough necks after loading.
I've never run into this problem in the past and was hoping someone could enlighten me a bit.
 

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Did you lube the case necks? Did you chamfer the inside of the case necks prior to seating the bullets. Funny looking marks -abnormal vertical striations on the case necks, did they go into and back out of the sizing die when you neck sized- should have required minimal effort. Could be a faulty die or problems with a compressed load? Does a friend have a seating die that you can borrow to see if that eliminates the issue that is occurring?
 
Those bullets look very deep in the case. What is the load data? How much powder crunch did you feel?
69.5 grains of RL22. COAL is longer than the specified length in Hornady book. I set them all at 2.683 base to ogive. I didn't feel any crunch. Checked case fill prior to seating and didn't expect any crunch based on volume.
They looked deep to me too, but they are longer than the book called for.
I was just throwing together a few rounds to rough zero the rifle after swapping to a new stock. Real load development starts after I quit hunting near my shooting area.
I've loaded, with the same brass, 74 gr of RL26 and the same bullet. This problem didn't happen with that load.
 
Did you lube the case necks? Did you chamfer the inside of the case necks prior to seating the bullets. Funny looking marks -abnormal vertical striations on the case necks, did they go into and back out of the sizing die when you neck sized- should have required minimal effort. Could be a faulty die or problems with a compressed load? Does a friend have a seating die that you can borrow to see if that eliminates the issue that is occurring?
Yes to lube and chamfer. Only ran the cases through a mandrel to uniform neck ID. Didn't use neck sizing die. Vertical striations were caused while seating bullet. Faulty die would be my first guess, and I received the new one today so I can test it. I just don't want to try the new one until I'm reasonably sure something else isn't screwed up. I've ruined one, and that is enough for me.
I can't shake the feeling I've overlooked something. The same brass, same die and same bullets went together just fine previously. Only thing changed is powder.
 
On my .308 had a problem with hard seating for virgin Lapua brass. I tried sizing where I run a mandrel through the throat to get the .002 neck tension I was after. After try a few different thing and having no joy, I finally tried my Lee neck sizing die and afterwards, seating was normal. Apparently the squeezing the Lee die does on the neck against the mandrel got rid of whatever what causing the interference. Someone else a little while back had the same issue and saw what I did and tried it, and it work for him as well. So. . . you might want to give that a try and see if that works for you . . .??? 🤷‍♂️
 
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On my .308 had a problem with hard seating for virgin Lapua brass. I tried sizing where I run a mandrel through the throat to get the .002 neck tension I was after. After try a few different thing and having no joy, I finally tried my Lee neck sizing die and afterwards, seating was normal. Apparently the squeezing the Lee die does on the neck against the mandrel got rid of whatever what causing the interference. Someone else a little while back had the same issue and saw what I did and tried it, and it work for him as well. So. . . you might want to get that a try and see if that works for you . . .??? 🤷‍♂️
Copy that. I was thinking of running the brass through a sizing die then using the mandrel prior to seating bullets. Just to see if the problem goes away. The amount of pressure I had to apply to seat bullets was nuts. Left me measuring bullets, case neck wall thickness, and so on.
Tomorrow is "fix it day". I'll update with results.
 
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Hey DCAN! When I first started loading .300 Win. I kind of had some of the same issues. The reloading book I have to go by was the Berger manual and they list all loads in the .300 Win at SAAMI seating depth. They just list SAAMI C.O.A.L. If you use big long bullets(are you using a long heavy bullet?) it's really hard to seat those at SAAMI depth. If you're trying to seat long bullets that deep with a Forster benchrest die (is that what you're using?) those seating stems are pretty thin on the ends making them unsuitable for compressed loads of that magnatude.

I ended up using a cheap Lee dead lenght seater die before I came up with a different load that seated the bullet out further. They have big thick "seating plugs" allowing you to really cram down the powder and bullet. Maybe go with a longer seating depth if your chamber/magazine situation allows it. I just had the same problem with a Forster benchrest seating die and mine wasn't even a compressed load I just messed up with one case. I forgot to chamfer the inside neck and it went in hard and distorted seating stem.

I don't have a Hornady manual so I don't know if they advise on seating depth or just opt-out to just SAAMI spec across the board, Some manuals have alternate seating depths with longer bullets. I think Sierra does and Lee does. My Berger book is straight SAAMI C.O.A.L
 
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Hey DCAN! When I first started loading .300 Win. I kind of had some of the same issues. The reloading book I have to go by was the Berger manual and they list all loads in the .300 Win at SAAMI seating depth. They just list SAAMI C.O.A.L. If you use big long bullets(are you using a long heavy bullet?) it's really hard to seat those at SAAMI depth. If you're trying to seat long bullets that deep with a Forster benchrest die (is that what you're using?) those seating stems are pretty thin on the ends making them unsuitable for compressed loads of that magnatude.

I ended up using a cheap Lee dead lenght seater die before I came up with a different load that seated the bullet out further. They have big thick "seating plugs" allowing you to really cram down the powder and bullet. Maybe go with a longer seating depth if your chamber/magazine situation allows it. I just had the same problem with a Forster benchrest seating die and mine wasn't even a compressed load I just messed up with one case. I forgot to chamfer the inside neck and it went in hard and distorted seating stem.

I don't have a Hornady manual so I don't know if they advise on seating depth or just opt-out to just SAAMI spec across the board, Some manuals have alternate seating depths with longer bullets. I think Sierra does and Lee does. My Berger book is straight SAAMI C.O.A.L
I believe the seating stem thickness, or lack of, may have been the issue.
I tried using my new Redding seating die and everything worked fine. All other variables (except powder) were the same as when the problem happened. I tried swapping the belled out seating stem for a new one from a non-benchrest Forster and it worked fine. Granted I only tested a couple loads, and it may take a few to bell out the stem. Time will tell.
The new seating tests were done without powder. On the initial loads, the ones which started this whole thing, the high seating force was evident as soon as the bullet seating operation began, long before the bullet could have contacted powder. I've wondered about the compressed powder issue, since that could easily explain what was going on. I am reasonably sure I didn't have a compressed load. According to the Hornady books fill volume numbers, I should not have been close. I also inspect each round, prior to bullet seating, just to be sure there really is powder in the case. The powder level I saw should not have created a compressed load issue. But, who knows. Wouldn't be the first time I was wrong.
Today the new seating die gets tested with a powder charge. Be interesting to see what happens.
Thanks for the input!