7mm rem mag brass life

[razorback2003]

I have developed a moderate and accurate load of 62.5 grains of H4831, Remington brass, and Hornady 139 grain BTSP's. I bumped the shoulders back enough on the once fired factory cases so that they will chamber. What kind of brass life am I looking at? Do I need to use my lee collet neck sizer to increase case life or will bumping the shoulders back every time I resize be the best idea?

I have noticed that after the 2nd firing of the brass (first firing of the reload) the brass does not seem to grow in length like the first factory firing did and also measuring for headspace with my Hornady tool does not show much of a change on the second firing.

 

[rcmodel]

That's because the case was head-spacing on the belt the first firing.

It doesn't stretch nearly as much the second firing.

Because you were wise enough to size them correctly to head-space off the shoulder instead of the belt.

I can't give you a number, too many variables like what load pressure you are running, etc.

But, it will be a lot more times then pushing the shoulder back and head-spacing off the belt like factory ammo!!

rc

 

[jwrowland77]

RC nailed it.

I do the same thing as you razorback2003, where I bump the shoulders back .0015", which is just enough to chamber the round.

I have a Rem 700 and I use two different loads. One for my daughter which is 57gr of IMR 4350 and one for me at 62gr of the same powder. I use the same 139gr Hornady BTSP (extremely accurate), and I have as many as 4 firings on the upper range load. The lower range I have as many as 6 firings. I also anneal my brass every other firing as well.

 

[Blue68f100]

I've got some brass that has over 6 firings on it. Like you I only bump the shoulder back enough so they will chamber. I do anneal the brass ever 2 firing, for my loads are hot. Have yet to have one fail in any manner. My brass is going on 4 decades old.

 

[TimSr]

I've got some with 5 or 6 firings, about 20 years old that still look good. Not a high volume plinker round for me. . Most of my other rifles are old milsurp, and I find that the condition of the gun's chamber is the biggest factor is rifle brass life for me. My 7mm RM is a 1970's Model 70 Winchester, and its easy on brass.

 

[Bart B.]

People correctly sizing 7 Rem Mag cases in full length dies with normal safe max loads got 15 or more reloads per case. Just set the fired case shoulder back no more than .002".

 

[stoky]

I've gotten more life using a collet sizing die, in addition to bumping the shoulder back.

 

[razorback2003]

65 grains of H4831 is the max load for the 139gr Hornady BTSP according to the Hornady book, so I'm below max with my 62.5 gr of H4831.

Do you think using the Lee collet neck sizer gives increased case life over just bumping the shoulders slightly back as long as the brass will chamber?

 

[matrem]

That belt cost me case life as well when first starting out. Once I realized to adjust die slightly, so shoulders were barely moved, case stretch was minimal.

I also learned years ago that since I was shooting them in a bolt gun, I could tweak that die a little more and not even touch that shoulder.

About every third loading return that die for a slight set-back because they'll get about where you feel you need to 'jump' on that bolt to close em.

After learning all that, getting a dozen or so out of a single case has been the rule.