I am fairly new to reloading and this is my first experience with tsx's. I just loaded some 150's for my 300 RUM and while measuring oal I was actually able to push the bullet further in the case with my caliper. I was even able to pull the bullet back out with my fingers! The expander button is at .306 and I would think .002 would be enough tension to hold the bullet. No wonder I can't get this gun to group real well. The recoil is probably pushing the bullets further in. I may switch to accubonds if this is going to happen. The brass is only once fired and I'm using Redding FL dies.

Expander ball is too big.
------------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

quote:

Expander ball is too big.

and/or your brass is too hard. Those supermag pressures are pretty hard on brass.

You don't say what brand of brass you are using but it sounds like the necks are too thin. Have you neck turned that brass? Is your Redding FL a neck "button" type? And do other brands of brass work okay?

To test what your die and expander are each doing, size a case normally and mike the neck. Then, remove the expander/decapper and do it again. (Same case.)

If there is a great difference between expanded and unexpanded and you can't seat a bullet with your fingers the second time, your expander is too large. If there is little or no difference and you can seat a bullet by hand both times the die neck is too large or the case neck is too thin and the expander isn't doing anything at all.

I've had the same problem with TSXes. The bullets are sometimes so loose in the case, you can easily move them by hand and I don't think it's a problem with the expander ball being too big since I've never had this problem with any other bullet I've loaded.

First of all, the TSX is harder than a conventional copper jacketed lead core bullet so there is little or no conformation to slight dimensional irregularities in the neck. Secondly, all the grooves on the shank of the bullet, decrease friction from the case neck on the bullet. Lastly, I believe the expander ball in pulling on the neck on the way out, leaves the part of the neck nearest the case body slightly larger in diameter than at the case mouth. Since TSXes are so long the base of the bullet will always be clear inside the case so only a tiny portion of the neck will be trying to hold the bullet.

As far as solutions are concerned, I haven't found a good one for the 375 H&H Magnum cartridge. In my 30/06, I've found that resizing the necks with a Lee Collet die and/or crimping with a Lee Factory Neck crimping die solves the problem nicely.

I'm using Remington brass. Does anyone else even make brass for a RUM? I would sure hope I can get more than 1 load out of the brass before it starts to get brittle. For me to load it .045 to .055 off the lands like I keep hearing, the case mouth is in the last fowling groove. That doesn't leave much surface area between the bullet and the case.

Brad, I've never got a 150gr to group well out of my 300. I had to go 180gr......wapiti7

Brad, did you measure the diameter of the loose bullets?? It just *might* be that Barnes delivered a batch of undersize bullets. That was not unheard of in the past, and although Barnes' QC has become a lot better, it might just be possible...

.002" neck tension (bullet - expander diameter) is not a whole bunch - even if you take brass springback of maybe .0005 or so into account. You might consider polishing down the expander ball just a tad - if you have problems with neck tension, that is.

- mike

The 150s may never group good. In my 300SAUM the lightest that shoots good is a 165. I use bushing dies and don't use an expander at all on any of my dies. If you want to use your current die just put the expanded in a drill and knock a thousanth or 2 off of it with a piece of fine sandpaper between your thumb and finger. It is real easy to do and quick.
Now load some 180s in the Rum and get tight groups.

I shot it today and found 6 shells last night that seemed to be good and tight. I kept them separate from the rest. They were the first ones to shoot real well. I bought some 165 accubonds and now am working on loads for them. They shot real well out of my 300 wby. It just seems easier to try a different bullet. I just sized all of my brass and the inside neck diameter was .306 just like the expander ball. Thanks for everyone's input. I now have to get my Zeiss fixed. The glass on the eyepiece has a chip or schmutz(technical term, I know) just to the left of the reticle on the inside of the scope. What a great weekend.

Stick the stem in your drill press, lock it down, turn it on, then take a new bastard file and hold against the expander ball slowly moving the file forward until you hav turned another .002 off it, then wrap the file in 400 grt. and polish the expander ball....or you can do the same in a lathem, or order a smaller expander ball from RCBS..that will solve your problem.

Some bullets are two demensional, some have a different ogive and seating them too deep can cause such a problem as yours. Get your mics out and check the bullets. Most monolithics are very long for caliber and weight and that can also be a problem in factory magazines and chambers.

I just started using TSX bullets in a 300Wby,300WSM using 180gr,168gr and 165gr haven't tried them in the 300RUM yet. I'm using bushing dies and haven't had a problem and I have loaded the same case appr 4 times in each caliber and I also chamfer case mouth seems to seat easier.

What I would look at after sizing the case is mike the inside neck dia you may not be getting enough spring back to hold the case with a .306" expander ball as some have suggested.

As with all new bullets I mike them just to make sure on my bushing size and they all miked .308 ahead of the boattail and between grooves. Well good luck

Brad from ND,
I had the same problem with .257 Weatherby, 7mm STW, .308 Win., .375 H&H and .416 Ribgy. For whatever reason the TSXs don't get the same grip on the neck as conventional bullets. I miked the bullets and none were undersized. Polishing another thou off the expander ball to give .003" under worked everytime..002" isn't enough. The same cases sized in the same dies held onto conventional bullets like grim death.

Brad,throw your crappy dies away and buy some bushing dies.I recommend Wilson and Redding dies.