Case Sizing Question

Crohnos01 · Dec 29, 2013

Ok, so I have been reloading for a lot of years now, but I came across an issue that I don't have a ready answer for. Not that I know it all, but I have the basics down pretty well. Maybe one of you guys who do this all the time have run across this?

I have reloaded for my own rifle (7mm Rem Mag) and my hunting buddies (also a 7mm Rem Mag) and never had an issue with what I am about to describe, but we have always kept our brass separate from each others. When he has a box of shells to load, I do those up and when I have a box, I do mine afterwards so there is no mixing of brass. As I say; no muss, no fuss.. load the round, it chambers, squeeze the trigger and get a satisfying bang. This has been the case (pardon the pun) for years now.

Recently, I had gotten my two sons rifles for hunting (also 7mm Rem Mags...what can I say... if it ain't broke, don't fix it). Both of their guns were from the same manufacturer (Savage Arms), but different from mine. Living in the same household, shooting at the same time, we managed to somehow mix up our brass. I didn't think too much about it and just loaded it all together.. then came the problem. All of the rounds will chamber in my Sako 7mm, some will chamber in one of the Savages, but not in the other and visa versa.... What's up with this? I use full length sizing dies but it seems like the shoulder is pushed forward enough on the cases that they won't chamber on one or the other of the Savage rifles. Shouldn't this be remedied with a full length sizing die? How do I fix this other than the obvious "DON'T MIX YOUR BRASS" (I put it in all capitals so I can yell at myself and save one of you guys from doing it for me)

oremike · Dec 29, 2013

My guess is that you've set your sizing die slightly off the shell holder, there by only neck sizing the cases, I'll bet if you adjust the die to bottom out on the shell holder they will work in all the guns.

Crohnos01 · Dec 29, 2013

Thanks for the reply. I was kind of thinking the same thing, but haven't had the opportunity to check it out. I just had never run across this particular issue before.. if indeed this die adjustment turns out to be the problem, I will have to make a mental note to make sure I double check that I have the die just touching the holder.

orygun · Dec 29, 2013

I had one set of dies that caused a similar problem for a rifle in 7mm-08 and it had nothing to do with them being fired in a different gun. In fact, you should be able to take a case fired in any rifle in 7mm and full length size it, then stick it in your gun and go.
But, if the chamber happens to be on the short side of specs and the sizing die on the long side, you'll end up with a problem like this.
If you find that your sizing die isn't contacting the shell holder during sizing, you've likely found the source of the problem. Make sure you check this when actually sizing a case. Your press may flex a little and not show the gap between die and holder until under stress. If the die is still set right, then you've probably got the same problem I did. I solved my problem by grinding a small amount off of the die so I could size the case down just a little more.

What was happening to me was as follows.
New ammo chambered, fired and extracted perfectly. Case fired in gun would re-chamber, but resized case would not. The die was squeezing the case, as it should, which slightly lengthens the case. Then the shoulder of the die is supposed to push the shoulder of the case back to the proper length. When the die contacted the shell holder it hadn't completed the stroke needed to move the shoulder the last little bit. Grinding the bottom of the die allowed me to gain the last part of the stroke needed to make the re-sized case, and ammo, fit in the rifle.

I've reloaded for several bottle-necked cartridges and this was the only one with an issue. I use RCBS for most of them, but I'm using Hornady New Dimension dies for the 7mm-08.

Greenbug · Dec 29, 2013

When full length re-sizing brass used in one rifle that I am loading to use in another rifle I set up my FL sizing die to touch the shell holder, then give it another 1/8 turn or so. This results in a "cam over" or "hard bump" feel at the bottom of the press handle stroke. Try it, it has always worked for me.

bballer182 · Dec 29, 2013

oremike said:
My guess is that you've set your sizing die slightly off the shell holder, there by only neck sizing the cases, I'll bet if you adjust the die to bottom out on the shell holder they will work in all the guns.

This^^^

AMProducts · Jan 2, 2014

While all reloading dies are different, some are tighter than others, some are looser.

The problem is your die may not be getting the case sized all the way back to saami spec, I know this is a common issue for many people, I shoot lots of range pickup .308, for which I use a small base sizing die, otherwise it can be pretty tough to chamber depending on what the guy shot it out of before I got it.

As a few have said, you may not have the die down far enough, it's an easy fix, try that first. If it's not that, you may need to look at getting a die that's tighter on the brass. Last I checked, I don't think anyone makes a small base die for 7mm....

rblsdad · Jan 3, 2014

I had this exact problem several years ago with a 270, turned out that the brass fired from an older 270, wouldn't chamber in a new 270. Not all chambers are exactly the same size, after we shot the newer 270 with factory ammo, it would take the reloads and chamber ok, try a few boxes of new factory ammo, than see if yoiu reloads will chamber.

scpaul · Jan 5, 2014

I'm new to this forum but I two have been reloading for a long time (30 plus) so I could afford to shoot. Try smoking the offending brass and try it , should show the area of your problem.

oli700 · Jan 8, 2014

Greenbug said:
sizing die to touch the shell holder, then give it another 1/8 turn or so. This results in a "cam over" .

This is the key to success

Crohnos01 · Jan 8, 2014

Thanks guys for the input. All really great advice; I hadn't thought about smoking the brass to see where the case is contacting the chamber; great idea.

I am in the process of completely demolishing and re-doing my reloading bench/area because I wasn't happy with the layout so it will be awhile before I get to check and see if these suggestions solve my problem, but as soon as I do, I will post back here with the results.

Thanks again!

shockme · Jan 8, 2014

head space -and chamber size

ron · Jan 8, 2014

Greenbug said:
When full length re-sizing brass used in one rifle that I am loading to use in another rifle I set up my FL sizing die to touch the shell holder, then give it another 1/8 turn or so. This results in a "cam over" or "hard bump" feel at the bottom of the press handle stroke. Try it, it has always worked for me.

Greenbug is right. The problem is the shoulder of the case is not sized enough. And it will not
chamber in a tight chamber.
Try this RCBS tool to measure new factory ammo and fired brass.
RCBS Precision Mic 7mm Remington Mag

Spitpatch · Jan 10, 2014

Greenbug's "cam-over" technique I thought was the very original instruction for full length resizing, and certainly is where we all started (or so I thought). In other words, "common knowledge". This is still standard practice for me when dealing with an unfamiliar (previously not messed with by me) gun and less-than-new brass.

bballer182 · Jan 10, 2014

Spitpatch said:
Greenbug's "cam-over" technique I thought was the very original instruction for full length resizing, and certainly is where we all started (or so I thought). In other words, "common knowledge". This is still standard practice for me when dealing with an unfamiliar (previously not messed with by me) gun and less-than-new brass.

I'm in the same boat. That's the way I learned and that's the current practice I use today. Have had zero problems to date.