Rifle doesn't like 77tmk's?

[eod.tek]

Has anybody had a rifle not like 77tmk's? I'm shooting a seekins sp15dmr, and have tried a large spread of charges with three different (ramshot tac, 8208xbr, and N135) powders, and the best I've been able to muster is a 1.3" 5 shot group. Most have been 2-2.5" groups. Im using lake City brass, CCI 400s, and my SDs are averaging low teens.

 

[Jason Snyder]

What’s the twist rate on the barrel?

 

[eod.tek]

What’s the twist rate on the barrel?

1:7

 

[Mulyhuntr]

Try a different primer? Gold medal match or rem 7 1/2.

 

[SamsonMan22]

I had a 1:7 barrel that hated 77 tmk with a variety of powders. I had the throat and mag length to use the 75eldm and they worked great. I shot 75bthp and also the 73eldm both of which worked nicely as well. If I were limited to mag length the 73s are what I would use of the tmk doesn’t shoot, if I had the room I would try the 75 eld with the 1:7.

 

[LaHunter]

New rifle, or do you have a load with a different bullet or factory ammo that your rifle shoots well? May want to try Varget as well.

 

[eod.tek]

Try a different primer? Gold medal match or rem 7 1/2.

If I can find some I will for sure.

 

[eod.tek]

New rifle, or do you have a load with a different bullet or factory ammo that your rifle shoots well? May want to try Varget as well.

New to me, but not new. The previous owner provided load data and pictures using 77smks and tac, but I can't replicate his results. Barrel has 900 rounds on it.
Mk262 I get right at 1-1.1" groups, and m855 I get 2-2.5" groups consistently.

 

[Formidilosus]

Has anybody had a rifle not like 77tmk's? I'm shooting a seekins sp15dmr, and have tried a large spread of charges with three different (ramshot tac, 8208xbr, and N135) powders, and the best I've been able to muster is a 1.3" 5 shot group. Most have been 2-2.5" groups. Im using lake City brass, CCI 400s, and my SDs are averaging low teens.

Throw it in the garbage.









Nah. I haven’t had one not shoot 23.5gr of 8208, LC brass, CCI primer, and 2.26 coal. Barrels are cheap, but if you don’t want to rebarrel try 73gr ELD-M.

 

[eod.tek]

Throw it in the garbage.









Nah. I haven’t had one not shoot 23.5gr of 8208, LC brass, CCI primer, and 2.26 coal. Barrels are cheap, but if you don’t want to rebarrel try 73gr ELD-M.

That exact combo yielded the below result.
Today I tried 23.0 and 23.5 and both grouped about the same.
Velocity on a 16" barrel was 2612 and 2630 and the group attached had an SD of 4 and an es of 12.5, so I believe the actual combustion portion was decent.
I was also shooting other rifles and they were grouping well, so I don't think I can say it was me either, although I suppose it's a possibility.
And for reference, I have swapped the scope onto another rifle and it grouped fine, so I don't think it's the scope.
I'm taking once fired LC brass, sizing with an expander ball, priming, throwing charges with a V4, and using 2.255 oal.
The biggest thing confusing me is that the guy I bought it from said it shot 77smks well, and not that I didn't trust him, but I looked in his post history and about a year before I bought it he hada few posts about how well the 77s were shooting , including a posted photo of a .6 inch 8 shot group using 77smk and tac. So, at some point this rifle shot 77s well enough.

 

[Formidilosus]

That exact combo yielded the below result.
Today I tried 23.0 and 23.5 and both grouped about the same.
Velocity on a 16" barrel was 2612 and 2630 and the group attached had an SD of 4 and an es of 12.5, so I believe the actual combustion portion was decent.
I was also shooting other rifles and they were grouping well, so I don't think I can say it was me either, although I suppose it's a possibility.
And for reference, I have swapped the scope onto another rifle and it grouped fine, so I don't think it's the scope.
I'm taking once fired LC brass, sizing with an expander ball, priming, throwing charges with a V4, and using 2.255 oal.
The biggest thing confusing me is that the guy I bought it from said it shot 77smks well, and not that I didn't trust him, but I looked in his post history and about a year before I bought it he hada few posts about how well the 77s were shooting , including a posted photo of a .6 inch 8 shot group using 77smk and tac. So, at some point this rifle shot 77s well enough.

Yes, but SMK’s aren’t TMK’s. My guess is that barrel has quite a bit more than 900 rounds on it.though it could be exceptionally picky.

 

[SamsonMan22]

Your groups above were similar to mine, I tried 8208, varget, n135, TAC, benchmark, and h4895. I got sick of wasting components and gave up on the bullet in that barrel. The 73 and 75 eldm shoot good with all of those powders. This was a typical 30 round group with h4895 and a 75eldm my barrel might have been picky but it would shoot if given what it liked. The major outlier was shot 30 and I’m sure it was me who botched it, give one of the eldm a chance they are a fine bullet.

 

[LaHunter]

That exact combo yielded the below result.
Today I tried 23.0 and 23.5 and both grouped about the same.
Velocity on a 16" barrel was 2612 and 2630 and the group attached had an SD of 4 and an es of 12.5, so I believe the actual combustion portion was decent.
I was also shooting other rifles and they were grouping well, so I don't think I can say it was me either, although I suppose it's a possibility.
And for reference, I have swapped the scope onto another rifle and it grouped fine, so I don't think it's the scope.
I'm taking once fired LC brass, sizing with an expander ball, priming, throwing charges with a V4, and using 2.255 oal.
The biggest thing confusing me is that the guy I bought it from said it shot 77smks well, and not that I didn't trust him, but I looked in his post history and about a year before I bought it he hada few posts about how well the 77s were shooting , including a posted photo of a .6 inch 8 shot group using 77smk and tac. So, at some point this rifle shot 77s well enough.

What brand sizing die and what brand / type seating die are you using? I have had good luck with Redding FL dies with the carbide expender ball and their competition seating die. What type of lube are you using on the case mouth when FL sizing? If the inside of the case mouth is not lubed properly, you can 'pull' the shoulders out of spec slightly. I use the graphite powder. How much are you sizing the shoulder back? May want to check out the Redding Competition shell holders. All of that matters, or at least it seems to matter in my reloading. Your reloading process could be the issue.

 

[eod.tek]

What brand sizing die and what brand / type seating die are you using? I have had good luck with Redding FL dies with the carbide expender ball and their competition seating die. What type of lube are you using on the case mouth when FL sizing? If the inside of the case mouth is not lubed properly, you can 'pull' the shoulders out of spec slightly. I use the graphite powder. How much are you sizing the shoulder back? May want to check out the Redding Competition shell holders. All of that matters, or at least it seems to matter in my reloading. Your reloading process could be the issue.

I'm using Hornady dies, and one shot case lube. I haven't been graphite lubing the necks on these but I certainly can try it, I have some. I'm only bumping shoulder back 3 thousandths and it's been pretty consistent. All definitely good points.

I have a buddy with 73 eldms, I'm going to try a few of them and try refining the sizing process for my necks and see if either one yields good results.

 

[Juan_ID]

I would have a hard time believing it’s down to what kind of case lube and or dies you’re using as to why your rifle doesn’t seem to like a particular bullet . I’ve used cheap hornady and rcbs dies with multiple brass types all lubed with 1shot since I started reloading and they’ve all produced acceptable results with various 73-77gr projectiles. I would almost bet the 73 eld’s shoot better without switching anything else.