300 WSm Bras Problem

[Elkslayer1]

Hi guys. Here is a pic of a full length sized 300 WSM case. As you can see, the last 1/8" towards the case end appears to be not getting sized and s actually smaller than the now sized case. Have double checked the setting on the die and it is perfect.

This case has probably been shot 3 or 4 times and has been full length sized each time. About 1 out of 12 of the cases will not chamber in the gun.

Any thoughts on why this is happening?

Thank you

 

[Canadian Bushman]

It looks like your chamber might be on the upper end of the spec. That would give you excessive headspace and cause your case head to stretch rearward upon firing.

The only thing you can do besides setting the barrel back, is to neck size only. Prolonging the case head separation caused by continually sizing the lower potion of case body more than it needs to be.

 

[Barrelnut]

The shiny 1/8 in. at the bottom of the case shows the height of the web area of the case. The shiny part usually or should not expand when fired. The less shiny remaining part of the case is what expands and holds the case against the chamber wall to seal the chamber when the round is fired. It is not unusual for the non-shiny part to be bigger after firing and after resizing.

I shoot 300 WSM also. I measured a fired case. measurement at the web was .552" and the measurement above the web area was .558"
After resizing it should be smaller about .001 or .002 difference. (Sorry but I don't have a resized case to measure t the moment.)

I would do these measurements on a couple cases that chamber after sizing and some of the ones that don't. Also check length and datum at the shoulder length. Issue may not be the line in the pic at all.

Having said all that, it does look like a huge difference in the pic. What are the measurements?

 

[Timber338]

It does look like there may in fact be an issue with your chamber like others have said. Just to offer another idea/thought, i assume that is Winchester brass... In my experience with win 300wsm brass is that wall thickness can be all over the place. I have gotten batches of brass that have neck thickness variations over .010", where the thin sections were down near .006" and they split after the first firing. I'm wondering if the brass you have that is not chambering is excessively thin near the web area. And add possible chamber dimension issues and the problem could be compounded.

Either way your intuition is correct in recognizing this as a problem that needs to be fixed one way or another. Good luck and keep us posted with how things pan out.

 

[jjmp]

your resizing your brass to much, thats why it growing in length.

no two chambers are the same,unless the same gun-smith chambered them with the same reamer.

set your die up so it headspaces on the cases front shoulder this keeps the brass

tighter and it expands less when shot, many die makers put great info instructions

with their die-sets. iv'e also fallen prey to this myself, but the info's closer then

we think, another sugestion is have a good gunsmith check your rifles headspace there could be many variables or just a few either way safety,is our

concern,regards an get back to us, jjmp

 

[Canadian Bushman]

This is a pic of a 308 case from one of my rifles, it has a similar problem as your case. This chamber is +.01 larger than a chamber i just had cut to +.002 over factory lapua brass.

Just as timber338 stated this brass has some high variations in thickness and when rolled on the table the case head runs out from the body notably.

 

[AZShooter]

Cover a tight fitting case with layout fluid or a sharpie then carefully insert directly into the chamber. Look for areas where it gets worn off. That will tell you where the bass is hanging up in the chamber. You might need a body bump die or even a small base die.

Unfortunately a standard FL die will move the shoulder more than necessary when you set it deeper to size the body taper.

Redding makes a body die. Whidden could help you make a custom sizer to suit your rifle's chamber better than a generic FL die from the big manufacturers.

If you have a access to a lathe you could modify another FL die to suit your needs. A carbide tool bit will cut through the case hardening on an RCBS die. If you cut off the shoulder/neck area and remove some from the bottom of the die you will have made a body taper die. You can really reshape the lower part of a case including the web if you so desire.

The idea is to reshape the case to properly fit your rifle's chamber.

 

[Elkslayer1]

Re: 300 WSM Brass Problem

Wow! You guys are amazing with all the help. Just a little more info, the two 300 wsm's we have are both using this brass for are
both factory winchesters.

The brass I am using is in fact winchester and most likely this brass has been shot 4 times and full length sized between each time. The wife and I like to shoot these guns a lot.

I measured the resized case above and her is what I got.. Shiny part on base is .55 and .59 above.

Agree with thinking the brass is not the best but I know what to look for now.

Measure a new factory winchester case that I sized out if the bag and it is .51 all the way thru. It loaded in both guns great.
Also grabbed a resized brass that measured .52 at base and .55 at the largest part on the brass. This brass loaded in both guns fine but the bolt did have a bit more pressure on it when it chambered. Not bad, just noticeable.

So, after resizing any brass ...I am going to measure and any brass that is over .55 will be thrown away. When brass was plentiful, I just bought new brass after it got to when it needed to be trimmed....I hate trimming and yes the brass above had been trimmed.

Don't want to run different brass in each gun as we hunt together all the time and want to be able to use each other's ammo if needed.

Here is my sweet wife with her 2013 Utah Bull Elk taken at 608 yards with one shot!!!! DRT..... Some guide was moving his shooter into position of this bull and he was on the back side of the ridge she shot it on. We did not know they were coming up the back side. The bull was on the top of the ridge ....they could not believe a shot came from that far away in the other direction. She was using her 300 WSM with berger 190 VLD. I am blessed to have this lady!!!

She was ****ed that we has to hike in 7 hard miles to get it!!! Oh well, trophy of a lifetime!! Scores 346

Here is her 2014 Utah Mule Deer. Scores 167

She kicked my A-- this year!!

 

[Timber338]

What a beautiful bull. Congrats to your wife and great shot too! So awesome that she dropped the bull before the guide/hunter got to it. Great story.

About the Winchester brass, I've always been disappointed that it's overall such poor quality. I reload for several WSM cartridges and now use Nosler brass. Very expensive, but very consistent dimensionally. I think if you sort the brass you have you will be fine, and very smart to be able to share ammo. And with a giant bull down with 1 shot from 608 it looks like you have plenty of accuracy.

 

[jjmp]

EKs 1,

your just as Amazing,hunting with your Wife is True Love,

Congrat's to you both, wonderful bull Great story great theacher BRAVO.......

regards jjmp

 

[Elkslayer1]

Thanks. Here is her deer that I could not get posted last weekend!!

 

[jjmp]

thank you

Just Wonderful

beautifully done, congrats jjmp