Tikka 223 Load Development & Accuracy Questions

[allaue87]

Hey all - I have tried 73gr ELD-M and now 77gr TMK with Ramshot TAC powder at various powder charges (22-24.5gr range) and also different seating depths (0.020" off the lands and also 2.260" COAL). I just cannot get a good group. Here are 10 groups from today and they are awful. Any ideas on what I am doing wrong? I am not a too terrible of a shot - with my Tikka 6.5 CTR I can get sub-moa no problem and close to 0.4-0.5 MOA on my best groups when I don't flinch/flyer. But maybe someone can see something going on with the groups?

The rifle is a factory T3X Lite that I dropped into a CTR stock with a CTR magazine.

I didn't label the picture with each load because they are all equally terrible, but here was my data with the 77TMK.
Row 1-2: 24.5gr / 1.893” CBTO
Row 3-4: 24.5gr / 2.260” COAL
Row 5-6: 24.2gr / 1.893” CBTO
Row 7-8: 24.2gr / 2.260” COAL
Row 9: 22.2gr / 2.260” COAL
Row 10: 22.6gr / 2.260” COAL

I dont have a picture for this, but this was my load data when I tried the 73 ELDM

Row 1: 23.9 / 1.880” CBTO
Row 2-3: 24.2gr / 1.880” CBTO
Row 4-5: 24.5gr / 1.880” CBTO
Row 6: 23.9gr/ 2.260” COAL
Row 7-8: 24.2gr / 2.260” COAL
Row 9-10: 24.5gr / 2.260” COAL

 

[kit.critchlow]

I'm sharing my load data for 223 eldms. Worked up in 2 Tikka t3x rifles. 20", 8 twist. One is a super light and one is a light. Pretty much identical load and velocities between rifles.

73, 75 and 80s tested.
Varget, staball match and Power Pro 2000 MR. RP brass from cheap ammo. I load on the hot side. I'm getting a slight primer crater but no other pressure signs.

Conclusion for me. 75 eldm with PP is probably ballistically best for longer range but the 80 is very close. One gun likes the 80 with PP a little better for accuracy.

.6 to 1.1 MOA 10 shot groups.

73 eldm - Max: 26.0 Varget, 2923 - 27.5 staball, 2916 - same velocity as 75 so didn't test any further.
75 eldm - Max: 25.5 Varget, 2850 - 27.5 Staball, 2920 - 29.0 PP, 3015
80 eldm - Max: 24.5 Varget, 2700 - 27.5 Staball 2800 - 27.8 PP, 2915

600 yd velocity w PP -
75 - 2065
80 - 2015

Pretty surprising results for me. I'm new to 223 loading though.

PP is slightly compressed, staball match is very compressed.

 

[Schmo]

@allaue87,
My particular Tikka 223 doesn’t like TAC. It may simply be your powder. Do you have any other applicable powders on hand?

For example, I’ll attach below my target. Every group on this target is spanning 2.5 grs of powder charge. I was just trying to find pressure.

 

[KingOfTagSoup]

Give Hodgdon Benchmark a try. I've been using that with a 69 gr TMK and I'm consistently sub moa, usually around .7-.8.......with a 300 dollar Mossberg MVP

 

[WestTN2288]

I like TAC with all those bullets… but you’re probably pissing in the wind. Seems like your gun just doesn’t like that powder. 24-25gr TAC is what I use with each of those bullets.

I’d leave your COAL alone and first swap primers for a 5x proof of concept. 10 more to verify. If you don’t like the proof of concept 5x, change powders. Go to Johnnys reloading bench on YouTube and watch his mk262 videos. The list of powders you can use here is pretty long

 

[kit.critchlow]

I like TAC with all those bullets… but you’re probably pissing in the wind. Seems like your gun just doesn’t like that powder. 24-25gr TAC is what I use with each of those bullets.

I’d leave your COAL alone and first swap primers for a 5x proof of concept. 10 more to verify. If you don’t like the proof of concept 5x, change powders. Go to Johnnys reloading bench on YouTube and watch his mk262 videos. The list of powders you can use here is pretty long

What velocities are you getting with tack on the 75 and 80 grain eldm?