6.5 mm tcu handload help

[modwerdna]

I have been handloading for years, and just ran into the first time I ever experienced over pressure loads using accepted data? I am loading for tc 14 " 6.5mm tcu. I started out by using 223 ammo and form firing them to my super 14 contender in 6.5mm tcu, neck resizing and then loading with 20 grains vargat behind
Hornady GMX http://www.hornady.com/store/6.5mm-.264-120-gr-GMX/

I instantly had flattened if not ruptured primers and hard case extraction, even though max load was listed as 25 grains. I dropped to 15 grains and still had the same signs but not as bad. Not till I dropped to 10 grains did it seem better?

I tried seating the bullet deep or sticking it way out and no difference, is it maybe because this is an all copper alloy slug and the twist is too fast (1 in 10)

They chambered up ok so don't think it's a neck reaming issue?-

I really wanted to try reloader 7 or 2400 but could not find any data for those powders- any experienced pointers appreciated (no armchair aficionados please)

 

[KansasSasquatch]

I'm not experienced with that caliber nor those firearms but I do know that using a solid like that will raise your pressures. Brass being lighter than lead its necessary for the bullets to be considerably longer to achieve the same weight as a lead core bullet. That adds to the bearing surface of the bullet and decreases case capacity, both can/will raise the pressure. The next heaviest bullets Hodgdon lists for that caliber are 129gr and 140gr. I think I would start with 140gr data. And if you don't mind me asking, where did you get Varget data for that caliber? Hodgdon doesn't list Varget. They do list BL-C2 which is slower, and every other powder they list is faster. From talking with Hodgdon, if they don't list a powder it's because they didn't find it suitable for the caliber or they just haven't got around to testing it yet. Calling them may be very helpful to you.

 

[modwerdna]

more details

I wanted to use blc(2) but with the ammo craze insanity it is a major project to find anything, and I had to drive an hour to get the Vargat, but here is a website I used - it seemed like a very well known site. I actually would have been happy to get either h 4198, or 332.... etc

http://www.lasc.us/RangingShotBullberry6.5TCU.htm#loaddata

last night I was able to buy a box of Hornady InterLock Bullets 264 Caliber, 6.5mm (264 Diameter) 123 Grain SST - these I believe are lead core, -

so should I give up on the Vargat?---- how about reloader 7, I use it alot on my 7.62 x 39

 

[KansasSasquatch]

I think Varget would be an acceptable powder, but I'd call Hodgdon. Maybe Hodgdon just hasn't tested it, but like I said, they may have found problems with it. If you're going to proceed without calling them, I'd suggest using the data for 140gr bullets listed on the website you linked to. It has 25.0gr Varget listed as the most accurate with 140gr bullets, but that may also be a MAX load. I'd suggest reducing it 10% and working up. So 22.0-22.5 would most likely be a safe starting point. But as I've stated, I have no experience with that cartridge, just experience with all brass bullets (specifically in the touchy 5.7x28 cartridge).

 

[modwerdna]

so I called Hogdon

So I took your advice and called Hogdon, great people to deal with, they suggested vargat was acceptable and it burns slower than h4895 - they also suggested the slug must be at fault, I will have to try and see, will update soon

 

[modwerdna]

final update -success

So I loaded up the Hornady InterLock Bullets 264 Caliber, 6.5mm (264 Diameter) 123 Grain SST and worked up to 25 grains of vargat and not a sign of overpressure - and the empty's popped out smooth as silk. So for me Contender 14" 6.5mm tcu and Hornady GMX solids DO NOT MIX!- maybe - " it's not a real bullet if it doesn't have lead in it?"......lol