Sierra Heavy TMK 6MM Testing

[HairyScandinavian]

Did a temp test with imr4350. 5 rounds in 0 degree freezer and 5 very warm wrapped in a hand warmer. I didn't have a thermometer to check temp. At the ranges I would shoot at an animal, say 500 yards, is a difference of .2 mil.
I wonder how much better performance I'd see with h4350 or n555

Did you chrono it? Curious as well about the H4350, goofing with GRT it shows more than expected velocity changes when I change the temperature, but I don't know where their model data comes from so not gonna blindly trust it.

 

[coya]

I

Did you chrono it? Curious as well about the H4350, goofing with GRT it shows more than expected velocity changes when I change the temperature, but I don't know where their model data comes from so not gonna blindly trust it.

I sure did.
Cold 2941
Hot 3029

 

[ID_Matt]

Shot the 107’s again today. I think these are going to be my go to for hunting season. Settled on 2970 FPS in the 18” 6 creed. Trending slightly low. Need to shoot it a bit further to true BC probably.

500 yards



600 yards

 

[KingOfTagSoup]

I've got the 107s in my 6 ARC bolt gun averaging 2777. Suppressed it's fantastic to shoot.

 

[Chris in TN]

Did you chrono it? Curious as well about the H4350, goofing with GRT it shows more than expected velocity changes when I change the temperature, but I don't know where their model data comes from so not gonna blindly trust it.

GRT uses a very generic one-size-fits-none approach to temperature. There's a mechanism within GRT that allows you to input your own temp data and calculate a predicted change per degree, but I've never tried to do anything with it. Most of my actual velocity testing is done from my barn window and the barn stays 50 to 75 degrees almost year 'round so I don't even worry about measuring that. If I'll be in extreme cold conditions I'll use the manufacturer's stated temp coefficients, if they're known.

 

[Jake Leibke]

I've got the 107s in my 6 ARC bolt gun averaging 2777. Suppressed it's fantastic to shoot.

What’s the details on the gun and load?

I’ve been trying to get them to shoot good. Best I can do so far is about 1.5 moa.


Sent from my iPhone using Tapatalk

 

[HairyScandinavian]

GRT uses a very generic one-size-fits-none approach to temperature. There's a mechanism within GRT that allows you to input your own temp data and calculate a predicted change per degree, but I've never tried to do anything with it. Most of my actual velocity testing is done from my barn window and the barn stays 50 to 75 degrees almost year 'round so I don't even worry about measuring that. If I'll be in extreme cold conditions I'll use the manufacturer's stated temp coefficients, if they're known.

Thank you for clarifying that, good info. I may toy with it some day but if I can shoot instead that's best.

 

[Plague]

Got out and shot some of my 107 6arc load with a buddies garmin today. 2975 average muzzle velocity. 31.5 gr of lever with a cci srm and Hornady virgin brass. 21” barrel. Slightly heavy bolt lift. 10 round groups are holding right around .8-.9 moa.

 

[Lawnboi]

I wonder how many people we would need to do a group buy for a bunch if 7 twist 6mm ace blanks with a .750 taperless contour and tikka shank size? Any interest?

I really want some cut rifle blanks in not a regular sporter contour, and not in a 1.2” shank, at a not crazy custom price…

 

[Jimbee]

I wonder how many people we would need to do a group buy for a bunch if 7 twist 6mm ace blanks with a .750 taperless contour and tikka shank size? Any interest?

I really want some cut rifle blanks in not a regular sporter contour, and not in a 1.2” shank, at a not crazy custom price…

I'd be interested

 

[Plague]

I wonder how many people we would need to do a group buy for a bunch if 7 twist 6mm ace blanks with a .750 taperless contour and tikka shank size? Any interest?

I really want some cut rifle blanks in not a regular sporter contour, and not in a 1.2” shank, at a not crazy custom price…

I would be into one.

 

[Treelineasassin]

I wonder how many people we would need to do a group buy for a bunch if 7 twist 6mm ace blanks with a .750 taperless contour and tikka shank size? Any interest?

I really want some cut rifle blanks in not a regular sporter contour, and not in a 1.2” shank, at a not crazy custom price…

I've asked Ace to make the taperless contours a few times, even sent them all the contour prints 8 months ago. They're slow to adapt......25 cal barrels were supposedly to be available 18 months ago, still nothing.

Ace only makes one centerfire contour that's smaller than 1.250", 1.200 is prob smallest they'd go. I'd personally have no issues asking my smith to turn that down @ Tikka 1.130" shank spec.

 

[Axlrod]

I wonder how many people we would need to do a group buy for a bunch if 7 twist 6mm ace blanks with a .750 taperless contour and tikka shank size? Any interest?

I really want some cut rifle blanks in not a regular sporter contour, and not in a 1.2” shank, at a not crazy custom price…

Yes 7 or 7.5 twist. I am planning on my second 6-7 PRC on the Raven action. I have an order in with Manson to grind a new reamer for 6-7 PRC, and there are no light contour 6mm barrels available right now. My current barrel is a Bartlein 7.5 twist. It shoots the Dtacs and the 116 TMK's very well.

 

[Lawnboi]

I've asked Ace to make the taperless contours a few times, even sent them all the contour prints 8 months ago. They're slow to adapt......25 cal barrels were supposedly to be available 18 months ago, still nothing.

Ace only makes one centerfire contour that's smaller than 1.250", 1.200 is prob smallest they'd go. I'd personally have no issues asking my smith to turn that down @ Tikka 1.130" shank spec.

I think they would be into it if we had 20 blanks sold.

 

[Treelineasassin]

I think they would be into it if we had 20 blanks sold.

Maybe, maybe not. A Tikka shank 750 taperless likely has more turning time than all their other profiles due to the amount of material being removed. Make 20 one off barrels, or 60 VCC/MTU in that amount of machine time?

Why not get a PVA Osprey in 750 taperless? Pretty sure he has 7tw as option. He sells contoured blanks, and prefits.

 

[Lawnboi]

Maybe, maybe not. A Tikka shank 750 taperless likely has more turning time than all their other profiles due to the amount of material being removed. Make 20 one off barrels, or 60 VCC/MTU in that amount of machine time?

Why not get a PVA Osprey in 750 taperless? Pretty sure he has 7tw as option. He sells contoured blanks, and prefits.

Iv got an osprey being chambered right now. Just looking for a premium cut rifles option. Hoping the osprey shoots good, but Iv had some really good ospreys and some ehh.


As for a smith turning down sure, lots of them don’t do it for free though, it essentially just adds money to the blanks.

I guess I could just buy whatever blank and see if LRI will recontour it for me. But even then it’s just more money and more time.

Ace makes tikka contour barrels already, reason I ask. I know bartlein won’t turn a shank down, atleast not last time I asked.

 

[Pistolpete28]

I was just as surprised

In my experience with the 107 tmk in a 243 tikka, I’m building my loads of of the listed max for the 108 Eldm. In my experience it builds pressure with less powder then the 107 tmk. I loaded up some 107s to 48.3 grains of h1000 and I’m also going to try 41 grains of h4350.

 

[huntnful]

I've shot the 116's twice now at distance to confirm what puzzled me on my first trip out.

The trued data I need to hit center at 1020 yards puts me 1 MOA (.3 mils) high at 700 yards.

I can't really make sense of that large of a discrepancy, but I've shot it twice now, once in the morning and once in the evening. Both times with good environmentals. Both times, same exact results.

That correction would put me at .31 G7 at 600-700 yards, and somewhere between there and 1020 yards it drops to a .28 G7. Just seems like a large drop. Not quite sure what to make of it, wondering if anyone else has any similar info?


The bullets also shot well on the last trip out. 5 shots into a .5 moa group at 622 yards and 4 shots into a .5 moa group at 1027 yards.

 

[Lawnboi]

I've shot the 116's twice now at distance to confirm what puzzled me on my first trip out.

The trued data I need to hit center at 1020 yards puts me 1 MOA (.3 mils) high at 700 yards.

I can't really make sense of that large of a discrepancy, but I've shot it twice now, once in the morning and once in the evening. Both times with good environmentals. Both times, same exact results.

That correction would put me at .31 G7 at 600-700 yards, and somewhere between there and 1020 yards it drops to a .28 G7. Just seems like a large drop. Not quite sure what to make of it, wondering if anyone else has any similar info?


The bullets also shot well on the last trip out. 5 shots into a .5 moa group at 622 yards and 4 shots into a .5 moa group at 1027 yards.

Is your barrel a 7 twist?

 

[huntnful]

Is your barrel a 7 twist?

7.5 twist