Hey guys,
My buddy has been doing some reloading with the 300 WSM and ran into a problem.

He's using Norma brass and after being fired once and full length resized they chamber tough.

I put some black magic marker on the case and saw a spot rubbed off at the top of the case neck.

I thought maybe with the pressures the 300 WSM operates at may change the dynamics of the brass. The brass seems like it's too thick at the neck causing difficult seating of the bullet.

Any ideas? I thought maybe get an inside neck reamer and even out the neck, but just thought I would check to others to see if there have been similar problems with reloading the WSM.

...or perhaps the chamber is rough and needs polishing.

Any suggestions would be really appreciated. Never had problems with other cartridges besides this one...

Thanks,
Mark.

I have a 300WSM. I was shown by my gunsmith that the gap between the shell holder and mouth of the die had to be set to .0025 inches to achieve the proper headspace. He had to shave off .015 inches from the shell holder to get enough slop to get this .0025-inch gap. The shoulder was too far up the case when the die was set to just snap against the shell holder. I have a SAAMI chamber cut into my barrel. My necks have a diameter of .336 inches. My cases chamber perfectly if I set the dies right. I also test-chamber every case after it's been resized. If it's been done right, the bolt will fall closed by gravity alone once I remove the striker assembly from the bolt. Not sure if any of this helps but if you can, you might try shaving .005 off your shell holder and test how well the cases chamber.

From what I`ve heard factory WSM ammo operates at very high pressures and combined with the thick brass that is used for it resizing can be tough.

Check to be sure there is no gap between the shell holder and the die when the ram is at the top of its stroke with case in it. If you can see "air" between the die and ram lower the ram and screw it deeper by ~1/8 turn recheck and if there still is no contact repeat until they touch.

I know a lot of loaders will ream the inside of a neck. Personally, I don't do it and disagree with it. Unless you have one hell of a concentric set up with a near perfect pilot, I just don't believe you can ream the inside of a neck and do a really good job.

Make sure the case lengths are within spec and turn the outside neck only.

Thanks for the replies fellas.

Will relay this info to him. He picked up an outside neck turner recently so if the die shellholder and resizing trick doesn't work we'll give the neck area a try.

To be honest. I don't find the performance of that round to be all that impressive. The factory loads list velocities on the box which the chrony isn't reflecting out of a 24" barrel, so I don't know...

I think a 30-06 does the job just fine, and of course the H&H for that matter.

The factory stuff does chamber fine, so the once fired stuff is a whole different animal that needs some attention.

I think a neck sizing die would not be a bad idea either if all else fails...

Thanks again!

Could be something with your buddy's resizing die.

I use Norma component cases, although I doubt very much if they are different than Norma uses for their factory loaded ammo. I load the 300WSM for a straight-pull Blaser R93 which doesn't have any of the cam action mechanical advantage of a turnbolt rifle. No problems with chambering reloaded ammo from my Forster die set on a Co-Ax press. But I have not reloaded any case more than 5 times so far. So your buddy's problem might be looming for me in the future once I resize my brass some more.

BTW, outside neck turning is preferable to correct lopsided case neck thickness. The attachment for the Forster trimmer does a good job for me. Although I have not needed it on the 300WSM brass.

quote:

Originally posted by 300H&H:
To be honest. I don't find the performance of that round to be all that impressive. The factory loads list velocities on the box which the chrony isn't reflecting out of a 24" barrel...

I think a neck sizing die would not be a bad idea either if all else fails...

Thanks again!

1. Factories have many powders that reloaders cannot use, thus many factory ammo achieve velocities we cannot. So, keep that in mind.
2. If the cases are not chambering with full length resizing and there is no problem with the sizing die and it is set up correctly, then neck sizing will not help. Usually if someone is going to run into a problem, the risk is lower with full length resizing and bumping the shoulder back .0005 preferably.

I understand he only loaded then once, but did he check the case length?? When cases get too long, they don't like to chamber.

Alright,
I will get back to you guys and see how the case length is too.

It may be that the dies are out of wack.

as I mentioned in my first post, if the case length is beyond spec after first firing and sizing, they won't chamber.

I had the exact same problem with both of my WSMs (270 WSM & 300 WSM) both are in Winchester M-70. What I found is that the face of the case head tends to "belly" (convex) sligtly when fired. When the bolt was closed on a previously fired but not completely full-length resized case, I would get a shiny rub mark around the primer. I suspect that it is due to the wider case head and possibly not enough thickness in the brass.

After experimenting some I found every thing was alright when I full-length resized the brass but I had to make sure my RCBS JR. press ram completely cammed over to achieve this.
The only other hitch I had was resizing lube.
After some suggestions from here at the forum, I found that Imperial resizing wax was the only lube that wouldn't leave dimples on the shoulder of the case and still provide adequate lubrication of the cases.

One other suggestion is to use the same brand of shell holder with the same brand of resizing die and of the same era of manufacture. There are differences in the dimensions between them all.

I had the same problem loading .300WSM's. On the 3rd loading, the case wouldn't chamber. As Homebrewer pointed out, there are headspace issues that develop. I sent my dies, holder and some fired cartridges off to RCBS and they do a quick machining and return at no charge. End of problem. This was actually on their website under the FAQ heading.

I was an early adopter of this caliber and I like it a lot. I never had any issue reloading except for the need to use good lubrication while resizing. I use Winchester brass, Hornady FL reloading dies and imperial wax. I do not turn or ream necks. I set the die to move the shoulder back 3/1000's each time I resize and trim the neck to the minimum length each firing. I annealed the cases after four loads. I'm on the 5th reloading of my initial brass purchase of 120 cases. I push velocities to the max measured by my Oehler 35P. The cases are in good shape and look like they will have no problem going 4 or 5 more reloadings.

My guess would be the Norma brass is slightly thicker than the Winchester brass, so it may require reaming, turning and/or trimming depending on the dies used.

As far as how it compares to other 300's, it definitely deserves it's fine reputation. I've owned the two different .300 Win mags and prefer the WSM for accuracy and ease of reloading. I really like the compact rifle designs and short action throw.

I think you friend will be very happy once he gets the loading issues sorted out!