Having problems w/ 300 Win Mag
 

Myself and a buddy chipped in together and bought a Hornady progressive press and have been loading for awhile now. The only problem we' ve run into is with the 300 Win Mag loads. We can only get them to go into the rifle properly if we use Hornady brass.

With any other brass we use, they won' t allow the bolt to close. We' ve measured overall length, case length, shoulder, case diameter from mouth to belt, wall thickness, everything!!! But we cannot find the problem. We' ve tried Winchester, Federal, and Remington brass. Dimensional wise, they are the same as the Hornady when we' re done trimming and sizing.

I might note, the loads with the hornady brass are tack drivers.

We' ve loaded .270, 30-06, and .45 acp rounds with no problems.

Any ideas?

RE: Having problems w/ 300 Win Mag
 

Could there possibly be an obstruction on the bolt face? How about the diameter between the rim and the belt? Maybe this will help, you never know.

RE: Having problems w/ 300 Win Mag
 

Several questions: Are you buying virgin brass and loading it or are you shooting the factory rounds in your .300 WM first?

Your gun: is it a factory made gun or custom chambered by a smith?

Are you full length resizing?

Whose dies are you using?

The .300 Win Mag headspaces on the belt like most belted cartridges.....these cases can also contact the chamber first on the shoulder just behind the neck and bullet. I had this happen with a .257 Weatherby....I thought my die was bad and I returned it to RCBS and they checked it and said it was good.

Have you taken a full length sized (empty) case that normally wouldnt fit the chamber and cut the case in half totally eliminating the foreward shoulder and neck to see if it does chamber under that condition?...If it does then there' s reason to believe your chamber is short.

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RE: Having problems w/ 300 Win Mag
 

Now that' s not fair. You' re not supposed to ask me more questions than I asked you!!! :D

We size down to the belt, but stop short of the belt by .0001" . Yes we use a full stroke down to the plate. The dies are Hornady. Yes, we shoot the factory ammo, then reload the brass, both with Hornady and the others. It does it in two different rifles. One is a Browning M1000 Eclipse, the other is a Browning White Gold Medallion. My buddy forgot to lube a case one time and got it stuck, then ruined the die trying to get it out, Hornady sent a new die, but the problem still exists. We kept the brass from our rifles seperate, but I don' t see what that has to do with anything if we' re full length resizing. We haven' t measured the diameter behind the belt. And no obstructions on the bolt faces. We both keep them clean. And, I' m sure we' re not setting the bullet too far out as empty, resized, cases won' t work either. I don' t have a shoulder angle measuring tool, but when we eyeball the case that won' t work, with the cases that will, there' s no visible difference that we can tell such as lengthening the shoulder.

Did I answer everything? Now you see why we' re kind of frustrated. [:@]
I noticed that the Federal brass seems a little more stout (maybe thicker or different grade of brass) than all the others.

Thanks for the help guys.

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RE: Having problems w/ 300 Win Mag
 

Danny45,

Consider picking up an RCBS precision mic chamber for the 300 Win Mag. It will tell you if your individual cartridge is in compliance versus SAAMI spec and if not then how many thousandths you are off by (in either direction). It will take into account the cartridge' s shoulder and belt as well. Be sure to mic the ones that work as well as the ones that don' t and note the difference in thousandths. At first blush, it sounds like it may be the die or the adjustment of the die.

Just on a hunch, before spending $$ or asking for refunds/exchanges, consider mounting the full length resize die in your old " one at a time" press, adjust it firmly and see if the problem persists. As stated above, borrowing someone else' s 300 win die and cross checking is a good move.

Best Regards
EKM

RE: Having problems w/ 300 Win Mag
 

Thanks guys. I' ll give those ideas a try.

RE: Having problems w/ 300 Win Mag
 

If the ammo originally fit into the gun and was fired, it means that the gun is probably fine and the brass is fine. Even if you don' t full length resize the brass should fit back into the gun!!! The bolt might close snugly....but it should close.

As you know, resizing (as well as firing) lengthens the brass...causes it to grow. I now believe your die is too long in the foreward end of the chamber allowing the brass to lengthen and then not fit back in the chamber.....However why one brand of brass doesn' t respond that way.....and my explanation don' t explain that.

As others have suggested....borrow another .300 Win Mag from someone and try it....I think you have a bad die!!

RE: Having problems w/ 300 Win Mag
 

Do the fire formed cases chamber before sizing? Have you tried just neck sizing?

RE: Having problems w/ 300 Win Mag
 

Handloader1, yes, and no. I had heard somewhere that with belted cases, it' s best to full length resize since they seat on the belt.

RE: Having problems w/ 300 Win Mag
 

Right off the top of my head the only cases that needs to be sized to headspace off the belt is the 300, and 375 H&H Mag. because of their shallow shoulder. According to the " Speer Reloading Rifle & Pistol Manual #12" " Modern belted Magnums like the 7mm Remington Magnum and the 300 Winchester have adequate shoulders for headspace control so the belt is actually more a cosmetic feature than a design necessary.
To get top accuracy from your belted magnum use the method described above to assure that the case headspaces on its shoulder instead of the belt."

If you neck size you will positivly be headspacing of the shoulder. Most die' s instructions for setting them up are for headspacing off the shoulder; be it full sizing or neck sizing. When people complain about belted magnums having to be sized off the belt to controll headspace, they are either trying to sell something, or are uninformed. A belted magnum case is just as accurate as a nonbelted case because one does not have to headspace off the belt; excluding cases simular to H&H Magnums. Good luck.

RE: Having problems w/ 300 Win Mag
 

Your problem is obvious! It' s a Hornady press! It is programmed to only use Hornady brass.[&:]

RE: Having problems w/ 300 Win Mag
 

I had a similar problem with a set of Hornady dies for a 6mm/.284. Although this isn' t a belted case, the problem may be the same. After repeated neck sizing, the cartridges began to be hard to chanber as the bolt was hard to close. Full length resizing didn' t correct the problem as it should have done. After making some measurements before and after the full length resizing process, I discovered that the F.L. die was not bumping the shoulder back. Hornady recut the die face by a few thousandths and everything worked just fine.

To measure for this, I used a trimmed .45 ACP case that I placed over the neck of the .284 case so the .45 case mouth rested on the shoulder of the .284 case. Then I used a caliper to measure the total length before and after F.L. resizing. The measurement showed that the case shoulder had not moved at all, so that proved that the F.L. die wasn' t contacting the neck as it should have. Hornady agreed that the problem was in the die and offered to recut the face ot the die as I requested. With .005 removed from the die face, it bumped the shoulder back approx. 0015" which then allowed the resized cases to chamber easily. If the shoulder had moved too much, I could have corrected that by backing the die off the shell holder by some small amount.

I know this is rather lengthy, but the measuring described took less time to perform then it took to write this. Hope this helps.