Got a problem

[hedditch]

I reloaded some 300 Rem Ultra Mag rounds for my neighbor. The load consists of 86 grains of IMR 4831 with a 165 gr Sierra bullet. It is extremely hard to lift the bolt after firing this round to where one almost has to beat on it. The chamber was a 300 Win and he had it re chambered to the 300 Rem Ultra Mag. (Believe it or not, the gunsmith did not remark the barrel). My neighbor said factory rounds have ejected just fine after firing. I had to really tighten down my FL sizing die to get the fired case of my hand loads to go back into the chamber. What are some of the other questions I need to answer for you to ascertain what my problem may be.

 

[Sully2]

One word...HEADSPACE! Totally new factory rounds should work A-OK because they are always "short"...but rounds fired in one chamber and then reloaded vary in length because of different ( slightly) headspace dimensions.

 

[243winxb]

factory rounds have ejected just fine, so its not the new chamber?

Hard bolt lift=reduce powder charge. Or go to a slower powder, like IMR7828. As for sizing, some rifles require the die to be truned down an extry 1/8 turn after contacting the shell holder. Plus the press may have some spring in it. Take measurement of the fired brass. Has the web area expanded more than normal? http://www.saami.org/PubResources/CC_Drawings/Rifle/300%20Remington%20Ultra%20Magnum.pdf Link to SAAMI drawings/measurements.

 

[fdshuster]

If the 300 Rem. Ultra Mag brass was loaded more than 2 or 3 times, it could be case head expansion.

Measure the diameters right in front of the extractor groove & compare once fired with the brass that resulted in hard bolt opening.

 

[markm87]

If the 300 Rem. Ultra Mag brass was loaded more than 2 or 3 times, it could be case head expansion.

He'd feel that when chambering the round no?

 

[fdshuster]

markm87: Good point. But I thought if the head is close to being "oversize", but the rest of the case is "standard" after sizing, the bolt may still close without any undue force required.

After firing, everything expands & that combined with the oversize case head, causes the hard bolt opening.

 

[hedditch]

I have measured everything and found the factory loaded round is .002 less than my reloads and also the fired rounds that I could hardly get out of the rifle just ahead of the extractor groove. As close as I could measure, all the rest of the measurements were the same. I am going to pull the bullets and start at 80 grs of IMR 4831. Any other suggestions?

 

[243winxb]

I would load only 3 rounds at 80gr to see if pressure is the problem. I feel its not a wise choice to reload for neighbor/friends. A rechambered rifle makes it worse. Sorry. :-\

 

[hedditch]

243winxb, you hit the nail on the head. Pressure was the problem. I backed off the load and the round came out after firing just fine. I loaded 80 grs of IMR 4350 as a test round with a 165 gr bullet. Thank you everyone for helping me out.
Dave

 

[oneflyer]

Which is it? 4831 or 4350? They are remarkably different powders.

 

[hedditch]

My first loads were with IMR 4831 then I switched to IMR 4350. The last round fired was with 80 grs of IMR 4350, the accuracy load in the Nosler book using that powder with the 165 gr bullet.

Dave