I reloaded my 375 H&H using once fired factory brass. When closing the bolt, right when it was closed and you rolled it over in the lock position it would close real hard but after firing ejected fine and acted normal.On my last shot when I ejected the casing I saw a thin brass wire like it came off the neck should I have trimmed these cases first or is there something else I am doing wrong ? Bill

You should check the case length. The 375h&h can strecth quite a bit on first firing, & depending on how you size them, can continue to stretch.

+1 on check your length.

My .375 chamber shaves brass on the edge of the belt recess at the rear of the chamber.

And also, some FLS dies will leave a sharp ring where they finish sizing near the belt. Maybe this got rolled off.

Thanks guys I couldn't believe how much the necks were stretched out. I trimmed them back and the bolt closes like a dream now.

bill.....

Now it is to check your Full Length Resizing Die set adjustment in relation to your rifles chamber, too.

You want to ensure that you are not setting the shoulder so far back as to create headspace which can also make cases appear to "Grow" or stretch alot after an initial firing, too.

quote:

Originally posted by billm:
Thanks guys I couldn't believe how much the necks were stretched out. I trimmed them back and the bolt closes like a dream now.

With all due respect and desire for constructivism here.....One really should not be reloading without such knowledge as checking and trimming to length AFTER FL RESIZING all his brass.

Every loading manual I ever picked up discusses this and states that it is critical and a necessary part of reloading.

May I strongly suggest you go back to reloading 101 and read the manuals.....it makes one wonder what else of a basic nature we might have missed here!

My 375H&H cases grow about .007" to .008" during resizing. I trim to the recommend 2.840" after every resizing.

The 100 cases I started with have been reloaded 3 to 4 times. Twice full length resized and twice neck sized (Lee FL die and Lee Neck collet die used).

After the 4th firing I cut a case in half to check on thinning of the case wall near the base.
I could see that thinning has occurred. I could not detect it with a feeler wire. It measured about .004" thinner than the brass wall just forward of the thinning ring.
The outside of the cartridge case did not show the bright ring mark like the pictures in reloading manuals show that foretells of imminent case head separation.
I will fire these cases two more times and section another case and check the thinning against the sample section I kept.

My RCBS precision mic tool shows that my Lee dies only set the shoulder back .006" from the fired state. (It was a real shock to see how new Rem brass is .008" to .012" shorter in head space ).

I think in the future I will put a .004" feeler gage between the shell holder and the die body when I full length resize so the shoulder gets worked less.
I may continue to just neck size then trim.

On my next batch of new brass I think I will forego the flash hole clean up step. After sectioning the case I didn't like how large and deep the chamfer was made on the inside of the case head.
I had used a sinclair model DB-1320 flashhole deburring tool that is suppose to prevent over cutting, it does do this but I feel it took too much brass off the inside of the flash hole, that is it made the chamfer too big and too deep.
The up side of this is I sure you could use standard power primers instead of magnum primers to power the case which might lower standard deviation in the loads.

quote:

Originally posted by greenjoy:
My RCBS precision mic tool shows that my Lee dies only set the shoulder back .006" from the fired state. (It was a real shock to see how new Rem brass is .008" to .012" shorter in head space ).

Setting back the shoulder .006 in FL sizing is excessive. Ideally, you are looking for .001 - .002"! The .375 H&H case will headspace on the belt, but you won't achieve optimal case life with that amount of shoulder set-back. Readjust your FL sizer and verify that your shoulder set-back is no more than (at most) .003 - better .001 - .002.

The number of times you can resize with your Lee Collet die is (largely) irrelevant in terms of case stretch and (partly) for case life.

- mike

I found this tool works well with my 375 H&H.

http://www.larrywillis.com/