7 mmwsm and fire forming for accuracy

[CrazyCanuck]

I am new to this forum but have been reloading for more than 20 years. This Browning A bolt 7 mm wsm is having issues trying for accuracy. I have checked many details and tried a few different loads, powders, and lead. My 110 ttsx is not staying very consistent. I will be loading some 120 and 140 ttsx bullets but I have never tried fireforming/ neck sizing as an option. I have decapped, tumbled clean, and measured different parts of the shell. New cases or resized cases have a outside dia of the neck that is about .004 - .005 thou smaller than the fired case. And the fired shell seems to load and eject normally. Should I try this reloading with just neck sizing? I will be reloading with the 140 Barnes ttsx and 315 magnum primers, and trying two powders. Imr 4350 and H 1000 as my two options. It seems that my mag only allows me to go to 2.850 COAL and this seems to leave .050 jump to lands. All the reading I have done seems to be GTG with this. My only other thing I would try is to machine the necks of the shell. Sorry for the long post but I would like everyone's input good or bad, maybe I am missing something. Thankx...

 

[Larryh128]

A 50 thou jump is totally fine for any of the Barnes bullets and may be slightly more accurate. You can try neck sizing but it is obviously a hunting situation and I would full length size them. I size mine so after any spring back the shoulder is .001 shorter than after firing. Alway chamber & case life is great. Are you talking neck turning when referring to neck machining? If so, it will definitely help you. You are just looking to clean them up so they are actually round. All my hunting brass get turned to .013 except the WSSM's that need to be thicker. Quite often you will only be cutting 1 side of the case.

 

[rogn]

You may want to try a different powder and primer combination. I had the best luck w/ 140 Barnes using RE-19 and CCI primers. Tula primers also worked well. I used the H-1000 w/ Barnes 168 gr. But the load was very compressed. Accuuracy and velocity were good with both combinations. Also, in the sticky section at the top of this section and hunting reloads, there should be a lot of favorite WSM loading data.

 

[CrazyCanuck]

Yes neck turning. Yes hunting situations. I have always full length resized on all my hunting loads over the years. 25/06, 270, 30/06, 308, 7mm wsm and have never had any problems on paper or hunting until this gun. I seems to hit and drop anything I have shot at but my paper is just awful.i was thinking that the 110s I was shooting might not like the 1 in 9.5 twist of this rifle and it might settle with the 120 s and 140 s. Thank you guys for all your replays, keep them coming with any other ideas.

 

[jonbearman]

I thought the ttsx bullets required an 8 twist to begin with.I seem to remember on the barnes site that the 8 twist is mandatory for accuracy with this bullet.

 

[CrazyCanuck]

Good thinking, as why I have some issues with accuracy with my 120 grain ttsx but Barnes site says 1:9.5 or faster so should be good. Anymore possible ways to tighten groups when I begin loading and shooting my 140 ttsx? Thankx...