So I loaded up 20 rounds of ammo for my little Mossberg .338 this past week, planning on going to range to today, so last night I decided to take the shells and the gun out on the patio and make sure that the rounds I loaded up are good to go, and not one of them would chamber.

I used once fired brass that I purchased a year ago or so, here on the fire. I full length sized them, and trimmed them, and checked all my dimensions and everything is at or close to spec ( nothing over spec), loaded them up, and they just won't chamber in the rifle I loaded them for.

Max case length I have is 2.488 ( book says max should be 2.5)
From base to top of shoulder I have 2.168 ( book says 2.169)
From base to bottom of shoulder I have 2.039 ( books says 2.040)

Neck dimensions are in or just under spec, base dimensions are all in spec.

So I went to the safe and got out the Win Model 70 .338 and the shells chambered fine.

So I go to the ammo cabinet and pull out other shells that I have loaded, they chamber in the rifle just fine, and I start comparing dimensions again, and everything seems to check out. Then I grab a box of factory loads and start checking dimensions, and confirm that brass is all checking out, and check the reloading manuals again, and nothing seems out of whack. Check to make sure the factory rounds chamber, they chamber just fine.

So guys I am at a complete loss at the moment. I am loading 180 Grain Accubonds, and I am actually seating them a tad deeper than suggested ( but the mossberg seems to like them that way) so my overall cartridge length is 3.28" and the book says 3.340"

So I ask you, what am I missing?

Thank you.

check the chamber for obstructions, clean the chamber??

Bump the shoulders back a little at a time till they chamber.

Is the bolt close to closing or not at all?

Check the dimension just above the belt. The rounds may have been fired in a rifle with a larger chamber than your Mossberg.Probably the same reason they chamber in your Winchester, a larger chamber.

You tested the brass in your chamber after you sized it? Differing reamers produce differing fired case dimensions, and dies don't always get them back to a dimension that will fit the reamer used on your chamber. When I get brass fired in another gun, I will size it until it fits in the gun I am working with, and no more. Sometimes, that isn't possible with standard sizing dies.

The bolt will not close on them.

Thanks for all the suggestions. I will see what happens, I am going to pull the bullets this evening, and start again.

Did the brass chamber before you resized it. Did it chamber after you resized it but before you seated bullets? If you don't check these things, you don't know where in the process something went haywire. Having BTDT I never load without checking everything in the rifle or rifles the shells will be fired in at each step in the process. Saves time spent with the bullet puller!

I'm with Buffalo Bill. I think that particular piece of brass was fired in a chamber larger than yours. Trouble is that your sizing die won't go down that far. One of the reasons I start with new brass and keep that brass with that rifle.
Phil

you screwed up seating the bullets. that's the only place it could happen..

I have seen spring back occur days after loading. I have also had rounds grow from compressed loads too. As other posted dedicated brass eliminates many of these issues.

Too much neck tension or really rough case mouths can cause brass distortion while seating. Bad die adjustment can too.

I would load and measure at each step of the process and then again several days later to look for changes.

Did you measure the width just above the belt? I had one rifle that needed the collet die. No resizing die would size that portion of the brass down far enough to chamber. Belted mag collet die fixed it. Rifle went down the road a while back to a guy that doesnt reload. Shot fine, just got tired of dealing with it.

That is exactly what the problem was. They chambered fine in one rifle, just not the other. It was something that I hadn't even thought about when I loaded them. The brass I was using was once fired brass that I purchased, and was not fired in either rifle of my rifles. My Winchester obviously has a larger chamber and will except the brass, the Mossberg will not. So I need to keep the brass for both separated. I have pulled the bullets and attempted to resize them but to no avail, as my sizing, as you stated, can not correct the problem. The Mossberg is my little beater rifle that I usually take into the thickest of thick places, so I just know that I will have to separate the brass.


Thank you all for your time and suggestions.

You can always get a Larry Willis collet die. (http://larrywillis.com/index.html) I've had to use this when moving belted brass from one gun to another. Now I just use it as a standard step in my reloading of belted brass. It allows me to move the rounds between guns without having to worry about it fitting.