77 TMK 8208 XBR load dev

[sveltri]

Did some testing today to see if I could find a good load. Components used: Tikka Super Varmint 24”, Starline 223 3x fired, rem 7.5, 8208, 77 tmk. Warmed up the gun with some factory 73gn match, then 23, 23.3, 23.6, 23.9, 24.2. Velocity #’s on the last group were Ave. 2888 ES 25.3 SD 8.7. Loaded the remaining brass at 24.2. 5 shot groups.

 

[swavescatter]

What neck tension are you using? I picked up about 50fps using a light crimp because I used a neck bushing that was slightly too big. Never saw this accuracy though.

 

[sveltri]

Not a bushing die, just a standard Hornady resizing die.

 

[doc holiday13]

I'd bet you'd get some good traction on this if you posted in the reloading section

 

[riversidejeep]

I should sell about 15 rifles that sit in the safe and get a Super Varmint .223, I've wanted one since the came out because they shoot so well and you have proven it again!

 

[Pharmseller]

You’re a grain over max, no pressure signs? Is 8208 temp stable?

I have a couple thousand 77 TMK but I got started on 75 ELDM and Benchmark but now that 8208 is hitting the shelves I’m getting curious.




P

 

[BringBackThe80s]

Nice! I'm testing 8208 and 77 tmks myself, but out of an AR with 20" bull barrel. Hoping to see some good results.

 

[rifletuner]

I have tried 8208 XBR in 223s with heavy for calibre bullets a few times, but never get particularly good velocities. Maybe it works better in shorter barrels rifles or semi-autos, since I have only tried it in bolt actions with 24-26 inch barrels. But for me, H4895 and Varget have been much better options.

 

[sveltri]

You’re a grain over max, no pressure signs? Is 8208 temp stable?

I have a couple thousand 77 TMK but I got started on 75 ELDM and Benchmark but now that 8208 is hitting the shelves I’m getting curious.




P

No detectable pressure signs. Bolt lift was normal, no ejector swipes, no primer punctures. I'll look again at the primers and see if I had any flattening.

 

[Jesse Jaymes]

This is my Go To combo in 223 AI. I very much love this powder. Most suggest TAC. I think XBR is quite a bit more FPS than max charge of TAC. My loads are over yours, but I am AI'd.

 

[Wrench]

My 223ai runs 24.3 8208xbr under a 77tmk at 2850.....and shoots about like yours.

 

[Lawnboi]

That’s a lot of xbr in a straight 223

 

[J_Jacobson]

That's a lot of powder in a saami 223. I found 25gr was hot in a 223AI with just the 75gr eldm.

 

[david2duck]

I’ve shot about 80-100 rounds of 24.0gr of XBR and the 77tmk. Also another 2-300 of the same combo except 75bthp. That load has shot well out of 3 diff T3X’s.

 

[Castle Rock]

No detectable pressure signs. Bolt lift was normal, no ejector swipes, no primer punctures. I'll look again at the primers and see if I had any flattening.

I think something is a bit off on your measurements, those top loads are really hot

 

[J_Jacobson]

I think something is a bit off on your measurements, those top loads are really hot

Agreed. ADI book max is 23.2gr with a 77gr projectile at 55,000PSI. 25gr would have to be way over SAAMI pressure limits.

 

[pbroski]

I think something is a bit off on your measurements, those top loads are really hot

Agreed. ADI book max is 23.2gr with a 77gr projectile at 55,000PSI. 25gr would have to be way over SAAMI pressure limits.

Maybe true for an AR. His bolt action can handle those loads without any problem at all.

 

[sveltri]

All I know is what I experienced. I did not see/feel any pressure sign at all. It is a bolt action Tikka Super Varmint.

 

[E.Shell]

We all readily acknowledge that any given rifle might hit high pressure before one reached 'book max' and just say "rifle variations!!" and "different components!". Why does no one ever believe a rifle might also safely exceed book max?

 

[KyleR1985]

All I know is what I experienced. I did not see/feel any pressure sign at all. It is a bolt action Tikka Super Varmint.

What’s the average H2O capacity of your fired/sized brass?

What’s the COAL of your hot load?