Any tips for a new TCU owner

[Crashnrondo]

I'm waiting for 2 bbls to arrive, a 15" 6mmTCU from Bullberry and a used 7mm TCU 10" VV bbl.  I plan on using 70gr BT's for the 6 and 120 gr BT's for the 7, and H4895 for the powder.  Any tips on resizing the brass or fireforming the brass, or loads for fireforming. should they be reduced?  Any info is appreciated

[kirkwhitaker]

they are easy to work with...remember this...when you size, do not set the shoulder back..or you will get headspace...when you do your fireforming load...i use a midrange load...not the starting load...and seat the bullet almost or just into the lands...keeps the casehead against the breechblock...
also....if you do get headspace..it will look like you are using a really hot load...will crater or even pearce a primer at times....so if you know the load is not max...and you get this...watch how you size brass... I have a 6.5 tcu...in a 10"...it shoots best when you are a grain or so below max load...just good loads...the 7 tcu will be a darling...easy to shoot and accurate...if done right...my 6.5 likes 120gr noslers and w748..yes it does make a fireball..but it will put them on top of each other at 50 yds and into an inch to inch and 1/4 if i do my part at 100yds...i took the scope off of it a while back and haven't shot it lately..but i am thinking about pulling it out and trying it with 130gr cast lyman's from a mould i picked up...those at 1500fps ought to be just pure fun...open sited fun gun...
my .02
kw

[KYODE]

in a lil test i did with my 6tcu, i fired 20 cases over and over. on the 7th or 8th firing i began getting misfires. headspace had grown too long and the action would not lock up completely causing the misfires. adjusting the size die down slightly to bump the shoulder back fixed it right up.

if h4895 doesn't produce in the 6tcu, try IMR4198, RL10x, Benchmark, or maybe even H335. although i've had most of my luck wih h335 using 80gr bullets.

[Lone Star]

Kyode is right, neck-sizing only with some die/chamber combinations will eventually cause case body lengthening.  I set my dies by smoking the case shoulder with a lighter and running into into the sizing die, screwing the die down 1/16 turn at a time until the smoke shows that the die is "just' touching the shoulder.  Then I lock the die in the press, knowing that it is doing the minimum amount of sizing needed for a perfect fit.

[bgjohn]

I use H335 or BLC2 in my TCU's. They are very accurate with 100gr bullets in the 6mm & 120's inthe 6.5.
JM

[kirkwhitaker]

they said what i ment...i smoke a case to set my die too...you want to size the neck and just barely touch/bump the shoulder...in my gun a full lenght resize will move the shoulder back way too far....and cause too much headspace..by touching/bumping the shoulder and not moveing the junction of the shoulder you keep it from growing...i get about 10 loads from my cases if i am using mild loads...oh, also...i have had best luck with new brass...i like the federal match 223 brass....best of luck...
kirk

[Crashnrondo]

Thanks for the tips, one more question can I substitute H4198 for IMR 4198?

[KYODE]

only if you start low and work up. should do that anytime anyway. :-)

[Jim S]

I have not owned a 6TCU (yet) but have had 6.5 and 7's and they liked H322 very well with the lighter bullets. My 10" 6.5 would group under 2" @200 yards with H322 and sierra 85 medium velocity bullet.