Author Topic: 300 win mag problems (Read 594 times)

huntswithdogs · « **on:** March 02, 2005, 09:29:55 AM »

I had a case head seperation the other day and need some advice.
The brass (R-P) was only on its 2nd load and was full lenghted sized. I owned a bolt gun in 300 before and never had this happen. I've always f/l sized. After the end came off of the first one I packed up and went home to check the rest before shooting them. I pulled all the bullets and rechecked all loads. Powder weights were what I had loaded(thankfully) and written down. After inspecting the brass really close,I found nearly all 19 remaining pieces showed the stretch marks right above the belt. I checked another batch of brass that I'd resized(once fired) and found a faint line on them also. This brass is evidently stretching badly! Could the chamber be too long? Could the brass be stretching when fired and my full length sizing is working it too much?

I've taken a new set of ten pieces and loaded them with the same loads. I hope to shoot them this weekend. As these were new pieces,I only neck sized them and will let ya'll know.

Robert

PA-Joe · « **Reply #1 on:** March 02, 2005, 09:58:31 AM »

There are several running posts on TCs and this same problem with mags. It seems to be a long throat problem. Some have backed off on their dies 0.006 and that solved the problem.

KYODE · « **Reply #2 on:** March 02, 2005, 06:36:05 PM »

if you resized untill the die bottomed out on the shellholder, it is possible that you pushed the shoulder back too far. this would overwork the brass and create excess headspace.
take a feeler gauge and check the barrel to frame gap. the first gauge thickness that will slide out with the gun closed should be very close.

remove the barrel. take a fired unsized case and push it into the chamber. note how much case sticks out of the chamber. keep adjusting your sizer down(relubing case each time) until the case sticks out of the chamber a couple thousandths less than the previously measured barrel to frame gap.
you should not size a case until it goes below flush with the chamber.

use the chamber as your gauge to setup your size die :-)

huntswithdogs · « **Reply #3 on:** March 03, 2005, 08:30:56 AM »

Okay, I'll shoot these this weekend and check the things that ya'll said to. The next question will be this...With neck sizing and shooting the cartridge from the same gun, will I need to trim these very often? When resizing as normal, I'd need to trim after 2 firings.

Should I be wary of the 25-06 barrel that I have also(for this same problem) or just go to neck sizing and be done with it?

HWD

PA-Joe · « **Reply #4 on:** March 03, 2005, 08:41:28 AM »

It's a matter of how far you are bumping the should back.

KYODE · « **Reply #5 on:** March 03, 2005, 06:20:50 PM »

i would recommend full length sizing only, but adjust the size die to only slightly bump the shoulder to fit the gun correctly as mentioned previously. use the chamber as the gauge. size until a couple thousandths less than barrel/frame gap of case sticks out of the chamber end of a removed barrel.

i check trim at each loading. i prefer trimming a couple thousandths each time as to having to trim 10 thousandths at once. the caliber specific lee trimmers are handy for this.

by only neck sizing you may run into problems of the action not wanting to cock on a loaded round fairly quickly. the problem being the gun not locking up completely because of excess headspace.........or the case being too long from base to shoulder.

size die adjustment is critical imo. kinnda hard to see a couple thousandths difference in amount of sizing.
i set my size die off the shellholder with the feeler gauges. the amount varies from barrel to barrel.