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.

 

[KY_coop]

H4895 was the first powder I tried with the 107s in my 18" 6 arc. Velocities were as expected around 2600. Accuracy wasnt fantastic. But im jumping them a country mile... 4995 was the trick for me with 108s

 

[95huskers]

Haven’t really had any great groups using H4350. Decided to try H1000. No pressure signs, so I’ll step it up. 20” PBB hybrid lite and OG6.5 on a Tikka.View attachment 1059918

Edit: Stepped up to 46.5gr and groups started to open up and SD started to climb. Went back to 46.2gr and shot 0.8” 10 shot group with an 8.9 SD and 2820 fps. I’ll stay right there.

I'm not new to reloading, but I AM new to reloading using GRT. I used to use slow burning powders on small calibers if that's what it took just like this and had pretty good luck, most recently with H1000 and 22 Creed. But now that I know the unburned powder values GRT kicks out, and now that I have suppressors on all of my rifles, I have somewhat deterred myself out of using them for whatever reason with the thought that efficiency is king.

For instance, I found a good load for a .270 I've been playing around with for a 20" barrel using H4831SC but the powder burn is only around 85% according to GRT. Therefore I have continued load development with faster powders. Can't get it out of my head.

My main question is, what impact does unburned powder have on a suppressor? Am I putting too much stock into this value?

 

[43.6N]

I'm not new to reloading, but I AM new to reloading using GRT. I used to use slow burning powders on small calibers if that's what it took just like this and had pretty good luck, most recently with H1000 and 22 Creed. But now that I know the unburned powder values GRT kicks out, and now that I have suppressors on all of my rifles, I have somewhat deterred myself out of using them for whatever reason with the thought that efficiency is king. For instance, I found a good load for a .270 I've been playing around with for a 20" barrel using H4831SC but the powder burn is only around 85% according to GRT. Therefore I have continued load development with faster powders. Can't get it out of my head.

My main question is, what impact does unburned powder have on a suppressor? Am I putting too much stock into this value?

First, a couple of truths to guide the thinking:
1. Gordon’s is a model.
2. All models are flawed.
3. Baffle erosion occurs from shooting. Fast powders/slow powders, all create hot pressurized gas. The heat and pressure will eventually wear down the device meant to restrict these hot pressurized gasses.
4. The shorter the barrel, the higher the muzzle pressure will be for the same powder charge (also applies to port pressures in AR15 gas systems).

I don’t believe there will be a meaningful change in my suppressor life if Gordon’s says I’m only getting 85% vs 100% burn. Especially when I consider the following:

I do believe the change in muzzle pressure between a 24” and 16” barrels will make a meaningful change in my suppressors life.
I would rather suppress a short rifle, rather than carry a long rifle.

So I must make peace with the idea that my suppressor (and barrel) is a consumable product that will eventually need to be replaced.

 

[Q_Sertorius]

I'm not new to reloading, but I AM new to reloading using GRT. I used to use slow burning powders on small calibers if that's what it took just like this and had pretty good luck, most recently with H1000 and 22 Creed. But now that I know the unburned powder values GRT kicks out, and now that I have suppressors on all of my rifles, I have somewhat deterred myself out of using them for whatever reason with the thought that efficiency is king.

For instance, I found a good load for a .270 I've been playing around with for a 20" barrel using H4831SC but the powder burn is only around 85% according to GRT. Therefore I have continued load development with faster powders. Can't get it out of my head.

My main question is, what impact does unburned powder have on a suppressor? Am I putting too much stock into this value?

If I am shooting 10-shot groups under an inch and getting velocity in the range that I want, a theoretical burn rate is totally immaterial.

As far as what it might be doing to a suppressor… are you shooting enough that this is a real concern? Let’s say that there is 5% more erosion on your suppressor (a purely hypothetical number)… does it matter in the grand scheme of things? I’ve never heard of anyone actually wearing out a suppressor (particularly a titanium one).

Edit - if I ever wear out a suppressor, I’m going to frame it and put it on the wall as a badge of honor.

 

[ckt3]

Agreed with @43.6N . I don’t have data or testing to back this up, but I don’t think unburnt powder’s impact on suppressor lifespan is worth worrying about. My intuition is that the delta in lifespan compared to baseline is effectively zero for a bolt action rifle with a reasonable barrel length and firing schedule. When you factor ammo cost across the suppressor lifespan, it’s a nonissue in my opinion.

 

[95huskers]

With the amount of $$ your responses are saving me in potential therapy/counseling costs to get it all out of my head I can likely afford a new suppressor anyway. lol

This is all kind of what I assumed, but I just truly didn't know. I also had questions on how much carbon build up can be expected versus a load with better powder burn efficiency.

 

[Q_Sertorius]

With the amount of $$ your responses are saving me in potential therapy/counseling costs to get it all out of my head I can likely afford a new suppressor anyway. lol

This is all kind of what I assumed, but I just truly didn't know. I also had questions on how much carbon build up can be expected versus a load with better powder burn efficiency.

A suppressor *can* be cleaned.

 

[43.6N]

Where I think unburnt powder can show up as significant is when dealing with ignition and burn consistency.

Example:
Some ball powders have a very clear threshold for how “clean” or “consistent” they might be. I’m shooting a lot of CFE right now. At lower charges they make a ton of soot. ES and SD are relatively high. But as I go up in charge, pressure increases, and the soot goes away. ES and SD and drop dramatically. This makes me think the burn is getting more efficient. Similar to running “lean” or “rich” on carbureted engines. My take away was that pressure is just as important for full complete burn consistency as anything else we track.