Rounds Hard to Chamber...Need Help!

[Patriot_1776]

I have had several rounds refuse to chamber with my 300 Wby.  I located the trouble spot due to a shiny area that was not there before.  I reload my ammunition, so I might be able take measures to prevent this from occuring, but I wanted to know what exactly is going on with them.  The trouble spot is located at the beginning of the shoulder of the finished case.  As you know, the Wby cases are double-radius design, but I can't understand why this happens now.  When I seated the bullet, the neck probably collapsed ever so slightly.   In turn, that caused a slight bulge to occur, very evenly around the shoulder.  The most common bullet that has caused it was the 180gr. Nosler Ballistic Tip.  While currently using the Barnes 180gr. TSX, after about 75+ of these it has only happened once so far.  I measured them with calipers, and my chamber-fired rounds measure .495" exactly, right were the shoulder begins.  The problem cases measure around .498" or so.  I believe what may be a factor, is the cases have been fired twice, therefore they are weakened somewhat.  What would be your diagnosis, and what would you suggest to prevent this from happening?  Any help is appreciated.  Patriot

[Graybeard]

Generally speaking when a shoulder collapses as you seat a bullet one of two things is causing it. One is that you have the die set incorrectly, too low and the die makes contact with the case too soon. When this is the problem most cases will collapse.

The other problem is you have it set so that a case over a certain length is too long and that's what I suspect is your problem here. Have you measured all cases? How do you have the die set? Best to use a case of maximum length before trimming is required and screw the seater die in until it just touches this case. Then any case less than that length will not give the problem you are experiencing.

Always measure every case after sizing to see if it has grown too long and needs to be trimmed.

Can't promise you this is the problem but generally speaking it is the most common reason for the problem as I understand what you are saying. At least in my experience it is.

[Patriot_1776]

One is that you have the die set incorrectly, too low and the die makes contact with the case too soon.

Ahh yes... Thank you for bringing that up.  Funny, I just remembered I had the die set up to seat AND crimp in the same depression of the press. :oops:   Please don't ask me why I have it that way, but I do know that when I seat the bullet the rest of the way (about .015".02") it crimps as it is seated.  That is probably it.  I'll reset it to not put a slight crimp as it does now, and I'll let you know if this continues or not.  I will also check OAL to make sure they don't need trimmed after resizing.  By the way, I heard something about leaving the round un-crimped will increase accuracy, is that true?   Patriot

[handirifle]

Patriot
One other thing that'll cause similar problems is too much lube on the case.  This usually shows up as a dimple on the shoulder area.

You really shouldn't have to crimp your bullets.  I just ran through similar problems with my 30-06 and realized I hade my re sizing die set too low, as described by GB.  It was actually causing the top of the neck to roll and made chambering hard.  A quick reference to the book brought that back to specs.  Not sure why I had it lower before anyway.

[Patriot_1776]

I will also check OAL to make sure they don't need trimmed after resizing.

I would also like to give that an extra detail.  95% of the time, I only do neck sizing.  Any reason I would use the FL die, is when the brass won't fit into my chamber due to expansion, or when I aquire once-fired brass from someone.  Afterall, if it's once-fired, they conformed to someone else's chamber, not mine!!!  Also, I do make sure I don't have excessive lube when I do FL resizing, so thanks for the consideration there.  Patriot

[Graybeard]

As already stated there is no real need to crimp at all. That's for lever action rifles and revolvers mostly.

[Lawdog]

Patriot_1776,

I have been shooting the .300 Weatherby Magnum for 41 years now and in all the time I have never crimped one.  I too only neck size except for the very same reason you stated.  Please post here if you find your problem but I believe Graybeard has you on the right tract.  Lawdog
 

[Patriot_1776]

OK!  I got to resetting my seater die, no crimp this time, and loaded 15rds. 40 min. ago.  Before I started everything, I trimmed all cases in use, made sure they are exactly the same OAL.  I measured the shoulder area, before and after seating the bullets (still TSX!!!) for the first 2-3rds.  They maintained the usual reading, .494" and stayed that way. :grin:   I don't see or feel anything irregular on any of them, so thanks all for the suggestions, and info.  I hope they produce some tight groups too.  I have 5 sets of three, starting at 81grs. of H4831, increasing at half-grain increments for every three, up to 83 grs.  My normal practice is to hand-weigh every charge for my rifles, to minimize any possibilty of innaccuracy due to variations.  

I have been shooting the .300 Weatherby Magnum for 41 years now...

Lawdog, in your experience, what powder has pleased you the most in this cartridge, both in performance, and accuracy?    Patriot

[Lawdog]

Patriot,

I used the old IMR-7828 for years.  Now I am trying RE 19, RE 22, H 4350 and H 1000.  Getting great results with Re 19, which is what I am currently using.  Lawdog