Sierra 107 TMK Load Data

[OFFSHORE]

Heavy for caliber OTM with a mediocre BC (MK-x) for hunting is kind of a hard sell in this market. Not at all saying it wouldn’t work fine but rather not sure what it does as good or better than the alternatives to justify picking it.

Agreed, just curious if Sierra may have changed/done something special with their lead alloy that would make them have a better terminal performance over the 107gr. SMK and 105 or 108 Bergers. Or did Sierra just keep things the same as the SMK line to jump into the long range hunting game? The jacket appears to be the same, or maybe it is just a change of wording on the label? I have a 6.5X55 IMP that LOVES the 144gr. SMK and it has been a great critter-getter for this rifle. . .as you said though, what does the MK-X line do as good or better???

 

[Formidilosus]

Agreed, just curious if Sierra may have changed/done something special with their lead alloy that would make them have a better terminal performance over the 107gr. SMK and 105 or 108 Bergers. Or did Sierra just keep things the same as the SMK line to jump into the long range hunting game?

They are not the same as SMK’s. Much better terminal performance.

 

[prairieboy]

Agreed, just curious if Sierra may have changed/done something special with their lead alloy that would make them have a better terminal performance over the 107gr. SMK and 105 or 108 Bergers. Or did Sierra just keep things the same as the SMK line to jump into the long range hunting game? The jacket appears to be the same, or maybe it is just a change of wording on the label? I have a 6.5X55 IMP that LOVES the 144gr. SMK and it has been a great critter-getter for this rifle. . .as you said though, what does the MK-X line do as good or better???

id assume much more open hp, thus the lower bc vs its comparable matchking variety.

 

[brucemt]

All 4 of these are 5 shot groups. Disclaimer; these were shot at 50 yards.

6 creed
20” pbb prefit
107 tmk @ 2.800
imr 4350

Previous to this I shot for pressure and had stiff bolt lift @ 40.5 and really heavy bolt lift @ 41.0

 

[MCGHeel]

Shot 10 rounds today 6arc Staball match 29.5 grains. No pic but group over 2”. First 10 round group at 30 gr was about 1.7”. Was hoping they would shrink with lower charge weight. Velocity is lower than I’d like but had some ejector swipes on starline at 30 gr so backed off for that too. I am very new to reloading so wondering what I should do next. I think change powders to see what it does, so I’ve loaded a little pressure ladder with cfe223 but haven’t shot yet. Mag limited for coal and I’m maxed mag length still about 0.095” off lands; Howa mini factory mags. Anyone think I should drop down to 29gr and see? I think that would be at or below 2600 and I’d really like to stay around 2650 if possible. Thanks for any suggestions. Chrono from 29.5 gr string

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[43.6N]

Shot 10 rounds today 6arc Staball match 29.5 grains. No pic but group over 2”. First 10 round group at 30 gr was about 1.7”. Was hoping they would shrink with lower charge weight. Velocity is lower than I’d like but had some ejector swipes on starline at 30 gr so backed off for that too. I am very new to reloading so wondering what I should do next. I think change powders to see what it does, so I’ve loaded a little pressure ladder with cfe223 but haven’t shot yet. Mag limited for coal and I’m maxed mag length still about 0.095” off lands; Howa mini factory mags. Anyone think I should drop down to 29gr and see? I think that would be at or below 2600 and I’d really like to stay around 2650 if possible. Thanks for any suggestions. Chrono from 29.5 gr string

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Virgin brass or once fired?
You’re still a full grain (or more) under expected pressure for a bolt gun.

Unless you’re 100% sure you’re seeing pressure, I’d resize and double check the higher charge

 

[MCGHeel]

Virgin brass or once fired?
You’re still a full grain (or more) under expected pressure for a bolt gun.

Unless you’re 100% sure you’re seeing pressure, I’d resize and double check the higher charge

Once fired. About 4/10 cases had ejector mark. That was the only sign I saw. Primers good, bolt lift fine. I do see Hornady maxes at 31gr for 108-110 data. Sierra stops at 29.7gr for 107 hpbt. Again, I’m new to loading but I “thought” I felt a little crunch or compression at 30.5gr. Coal 2.325. My biggest concern though is even at max or near max, accuracy wasn’t great anyway so thinking gun just may not like Staball match too much.


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[43.6N]

Once fired. About 4/10 cases had ejector mark. That was the only sign I saw. Primers good, bolt lift fine. I do see Hornady maxes at 31gr for 108-110 data. Sierra stops at 29.7gr for 107 hpbt. Again, I’m new to loading but I “thought” I felt a little crunch or compression at 30.5gr. Coal 2.325. My biggest concern though is even at max or near max, accuracy wasn’t great anyway so thinking gun just may not like Staball match too much.


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That’s a fair assessment. Lots of good powders out there. Varget and Vhitavuori N540 would be top of my list to try for accuracy with good velocity.

 

[MCGHeel]

Have some varget. Will give a try. Thanks


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[Bluefish]

Shot 10 rounds today 6arc Staball match 29.5 grains. No pic but group over 2”. First 10 round group at 30 gr was about 1.7”. Was hoping they would shrink with lower charge weight. Velocity is lower than I’d like but had some ejector swipes on starline at 30 gr so backed off for that too. I am very new to reloading so wondering what I should do next. I think change powders to see what it does, so I’ve loaded a little pressure ladder with cfe223 but haven’t shot yet. Mag limited for coal and I’m maxed mag length still about 0.095” off lands; Howa mini factory mags. Anyone think I should drop down to 29gr and see? I think that would be at or below 2600 and I’d really like to stay around 2650 if possible. Thanks for any suggestions. Chrono from 29.5

I just loaded up a batch of 29.5 cfe223 107 tmk at 2.300 oal. The previous batch at 30g was right at 2700 from a 20” barrel. I had a shoulder bump issue that was causing issues, so it was hard to tell what was going on as far as pressure, but QL says 2700 is 62k psi.

 

[MCGHeel]

Varget didn’t go great . Pressured out at 28 gr. I’d have to stay under 27 I think. Velocity pretty meh, 2513 at 27 grains. I’ll try some cfe and get some n540 if it doesn’t cut it. Pic of Varget 26-28 gr.

CFE 28-30 gr faint ejector swipe at 30 and better speed. We’ll see.


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[HairyScandinavian]

Anybody tried H4895 with the 107's in 6 ARC? I see both Hornady and Sierra have it listed for similarly weighted projectiles and I have a couple lbs of it I have no plans for. Looking to put my wife's bolt right at 2525 fps or so (16" RAR) so no sense in chasing speed with other powders figured it might be the ticket.