SR4759 seems to work well in the 7-30 Waters 14" barreled Contender, but this is my first foray with the 7mm TCU. Did some testing with jacketed bullets last year, thinking I would prefer to use cast bullets with this case as well.

Anybody have a favorite load for this combo in a 10" barreled TC Contender? (I do have several pounds of the currently discontinued(?) SR4759, so if that works well, no dramas!...for a while at least.)

Thanks!

In my 7TCU 10" Contender with the RCBS 145 I use the same load that I was using with 150 gr jacketed. This being about 23 gr of AA2015. I've had good results with H4895 as well. I found that the key to top cast bullet performance is using a suitable alloy and fitting the bullet to the chamber throat. I also nose size my bullets to be a slip fit into the rifling and seat the bullets as far out as possible. TC Contenders are noted for generous chamber throats. Fitting the bullet is the first and most critical step in developing the best load possible. As far as alloy, I aim for something with a BH of about 18.

Funnily enough, friend Kdiver58 bought up almost all of the AA2015 powder at our favorite shop recently for his .25 BR. May run by tomorrow and see if they have the lone 1# can left.

Now to sort the undersize necks left by the sizing die. Fine for jacketed, but kinda extra tight for CBs. Thought there might have been a collet sizing die from Lee, but may have to make a custom expander plug for the dies I already have. Wouldn't be the first time!

Adopted your bullet nose sizing trick last year for the 7-30 Waters. Works quite well indeed!

If you can find a Lyman M die for 7TCU that should work on those necks, too. I started shooting cast for my 22 Hornet and the M die works great.

StandingTall wrote:If you can find a Lyman M die for 7TCU that should work on those necks, too. I started shooting cast for my 22 Hornet and the M die works great.

In actual fact, that may be the easiest solution! Not too worried about the gas check area, just the rear drive band. The step may be just the right size or can be easily made so. And the 7mm M die is pretty generic, so may already have said about. If not, it's possible an old gun shop near by may have the right plug in stock. Heading that way soon, anyway.

Thanks!

Every cartridge case that I load with cast bullets is run through a Lyman M die. I also apply a slight additional flare to the case mouth with a Lee Universal case expander die. The point here is to be sure that you do not shave any lead from the bullet when it is seated or to have such a tight case neck pull that the perfectly sized bullet is squeezed down when seated. I have some custom expander buttons for my M dies that are slightly larger in diameter that those that Lyman supplies with their dies.

Also, in regards to powder selection, if you can't find some AA2015 you might want to try some H322 because the two powders are very close.

high standard 40 wrote:Every cartridge case that I load with cast bullets is run through a Lyman M die. I also apply a slight additional flare to the case mouth with a Lee Universal case expander die. The point here is to be sure that you do not shave any lead from the bullet when it is seated or to have such a tight case neck pull that the perfectly sized bullet is squeezed down when seated. I have some custom expander buttons for my M dies that are slightly larger in diameter that those that Lyman supplies with their dies.

Also, in regards to powder selection, if you can't find some AA2015 you might want to try some H322 because the two powders are very close.

Now have both! Picked up some H322 awhile back for some unremembered use, and some AA2105 last weekend.

BTW, If you ever shoot swaged bullets, I've found that "no" neck tension works best. Which helps explain (some of) the cannelures on .38 wadcutters, et al.
Has been a big part of getting my .44 loads to do as well as they have.

I use SR4759 exclusively in 7 TCU. Ballpark 13-15grs for most any bullet weight.

dan in mi wrote:I use SR4759 exclusively in 7 TCU. Ballpark 13-15grs for most any bullet weight.

Thanks!

Will give that a try as well.

M die delivered last Friday. Lower portion measures 0.282", which is a little small, but the upper portion is a nice 0.286" which is about ideal. A tad short shanked if I crimp, but is easily enough modded to suit. (Crimp, if nothing else, helps with live round extraction! Found that out the hard way with the 7-30 Waters.)

In my XP-100, I've had outstanding results with 15.0g of IMR 4227 and a 140g Sierra. H322 is my go-to powder for a Contender in 6.8 SPC and a 130g projectile, however.