Sierra 155g TMK

[LC 6.5 Shooter]

Just got a new .308 10tw Hawk Hills barrel. Anyone know how much jump the 155g Sierra TMK likes. Thanks.

 

[Jory45acp]

Bump for this thread as I'm interested as well.

 

[LC 6.5 Shooter]

Bump for this thread as I'm interested as well.

Sierra replied to an email and said they like touching to 0.015” jump. I haven’t shot them yet. They would have to be single load for me at 0.015 jump to touching. Would come close to fitting in my AI mags.

 

[Jory45acp]

Sierra replied to an email and said they like touching to 0.015” jump. I haven’t shot them yet. They would have to be single load for me at 0.015 jump to touching. Would come close to fitting in my AI mags.

Can your weapon accept AICS mags? I think one is slightly longer than the other but I'm not sure where I can reference that at. I know some bottom metal actions fit both, some do not. Touching to .015 I'm gong to have to see how much of the round is even in the case neck at that point. Seems like it's going to be barely seated.

 

[jarhead1077]

Model 10 FCP HS Precision .308, 24 inch : 155 gr. Sierra TMK over H4895 in Lapua brass. Originally shot at 0.010 jump. After about 1000 rounds chased lands and found ATL to be the best in my rifle. I have about 2200 down barrel now.

 

[towerofpower93]

Model 10 FCP HS Precision .308, 24 inch : 155 gr. Sierra TMK over H4895 in Lapua brass. Originally shot at 0.010 jump. After about 1000 rounds chased lands and found ATL to be the best in my rifle. I have about 2200 down barrel now.

ATL = at the lands?

Playing with this bullet in a 12.5” AR10 upper in .308 and the ES/SD are looking good, but haven’t really tried for groups yet and mag length is definitely a thing for this application.

 

[jarhead1077]

"At The Lands" yes but different application in your AR10 magazine situation for sure. Just basically saw 155 gr. Sierra TMK and responded without realizing totally different shooting application.

 

[towerofpower93]

"At The Lands" yes but different application in your AR10 magazine situation for sure. Just basically saw 155 gr. Sierra TMK and responded without realizing totally different shooting application.

Thanks for confirming the abbreviation.

I’m definitely mag length limited, but the ES/SD look good so I’m planning to run 20rds at 200yds and see what I get as far as group sizes and go from there.

Maybe my Ranier Arms Ultra Match barrel, which requires a small base resizing die, has a short throat and the 155 TMKs dig the lack of jump.

 

[Jory45acp]

I'm wondering which brand of mag for the AR -10 might offer longest internal space for loaded rounds?? Even .010-.015 extra length would maybe make the difference.