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Reloading Berger Bullets


7mm RUM reloading difficulties

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Unread 09-26-2005, 10:01 PM
Silver Member
Join Date: Nov 2004
Location: GF Montana
Posts: 467
Re: 7mm RUM reloading difficulties

I had exactly the same problem with a set of RCBS dies. Visual inspection after resizing showed it was not bumping the should back at all, despite being 1/4 turn past bottom. I tried chambering a bunch of the brass before I put the bullets in and verified the problem before I reloaded them. I posted the question and got the same answers (all wrong). I put blue ink on the neck and could see that's where it was hitting. Grabbed a set of LEE dies and no problems. I'm sending them back to RCBS. Turns out other folks have had that problem.
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Unread 09-26-2005, 10:52 PM
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Join Date: Jun 2004
Location: Fort Shaw, Montana
Posts: 6,841
Re: 7mm RUM reloading difficulties


Lets walk though this and figure out where the problem is occuring.

Step one, take a fired case and chamber it in your rifle. If you are running normal pressures the fired case should chamber even if it takes a bit of pressure on the bolt to lock her down. If the bolt will simply not close on a fired case you are WAY over pressure and need to back your loads off. If it chambers move to step two.

Step two, size the case in your usual manor, clean off any excess lube and again chamber in the rifle. IT should chamber at least as easily as the unsized fired case and usually even easier depending on the load level used.

If it will not chamber something is wrong with your sizing die which I doubt but it may be, just rule it out. If it does chamber then move onto step 3.

Step 3.

With no primer or powder in the case, seat a bullet to the same length just as you would with a finished loaded round. Chamber the round and see what happens.

If it does not chamber there are a couple things that can cause this.

A. The seating length for the bullet is to long and it is contacting the origins of the rifling and not allowing the round to fully chamber so the bolt can lock down.

B. The die is turned down to far in the press and its built in crimping shoulder in the die is trying to crimp the case mouth into the bullet. If there is no crimping groove this generally results in a slightly bulged shoulder which maked it nearly impossible to chamber in the rifle.

I would suspect this may be the problem. To check this, take a sized case that is know to chamber easily in the rifle, out it in the shellholder in your press, raise the ram to its highest point and then screw the seating die down until it just contact the case. Turn it back 1/16 of a rotation and seat the bullet to the proper OAL you want by adjusting the seating stem adjuster, not by turning the entire die down in the press.

Go through the steps one at a time and figure out at what point the case is being deformed out of spec. Then correct the problem.

Have a good evening,

Kirby Allen(50)
Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

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Unread 09-27-2005, 01:45 PM
Junior Member
Join Date: Oct 2004
Location: CenTex
Posts: 22
Re: 7mm RUM reloading difficulties

Thanks for all the great info guys. Ill be out of town for a few days, but I'll get back and let yall know the progress I make.

Thanks again! [img]/ubbthreads/images/graemlins/cool.gif[/img]
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Unread 09-27-2005, 08:43 PM
Gold Member
Join Date: Sep 2005
Posts: 750
Re: 7mm RUM reloading difficulties

Have you debures and chamfered the inside of the necks the factory's flare the necks and then crimp them so the cases do not need a chamfer. This can cause a dimple or fold in the neck when seating bullets as it can shave off fine shavings and stop the round feeding into the chamber it seems to me this could be a contributing factor. Try a bigger chamfer als are you crimping with the seeting die if you are you can be bulging the cases if the die is not exactly right if you are going to crimp get a Lee collet crimping die to crimp in a seperate opperation and back the seater off and try again.

Cheers Bill
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Unread 10-21-2005, 06:49 PM
Junior Member
Join Date: Oct 2004
Location: CenTex
Posts: 22
Re: 7mm RUM reloading difficulties

Just to let everyone know, we found out the problem. Thanks for all your input!

Seems as though, when trying to press the bullet into the brass, the bullet was hitting the edge of the die, more than the peice that you screw in from the top of the die.

This was causing it to go in partially crooked I think and warp the brass. Instead of the shoulder being staight, it ended up looking bowed more.

So with different brass and loading the bullet correctly, we fixed that problem.

Also, after I realized that the rounds we loaded the first time were not going to work...we tried to unload them. We have a hammer for this usually, but due to the extreme size of the round, it wasn't working, so plyers had to be used.

The teeth in the plyers ended up indenting the bullet, and ended up also causing trouble when locking down the bolt. However, after filing some on the bullet to "de burr" it, the new round goes in great.

As of now Im using an overall length of 3.7" with 104.5 grains of BFG50 Powder. Hollow point 140 grain bullet. [img]/ubbthreads/images/graemlins/cool.gif[/img]
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Unread 10-24-2005, 02:44 PM
Silver Member
Join Date: Oct 2005
Location: River City USA, East of the Mississippi
Posts: 280
Re: 7mm RUM reloading difficulties

You are most likely pushing the shoulder back when you seat your bullet. Back your seating die out and try again. After you seat your bullet check the diameter at the base of the shoulder. It sounds like you might be callapsing the shoulder and it won't chamber. Without the bullet it chambers after you resize again. Pull the bullet and try chambering the case without resizing. If you are colapsing the shoulder it won't go in without resizing. [img]/ubbthreads/images/graemlins/wink.gif[/img]
Nuclear Grade U.B.C. Ret.
NRA Lifer

People are like flowers, It's been a privilege to walk in your garden.
May the good Lord Bless and Keep this great Nation and may God smile upon our garden.
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Unread 10-24-2005, 04:17 PM
Junior Member
Join Date: Oct 2004
Location: CenTex
Posts: 22
Re: 7mm RUM reloading difficulties

Yup, thats what we did.

and after shooting those new hot loads! [img]/ubbthreads/images/graemlins/shocked.gif[/img]

WOW, after about 30 shoulder sure is soar! [img]/ubbthreads/images/graemlins/wink.gif[/img]
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