175gr Sierra TMK's

[smihtp]

Has anyone been shooting these relatively new pills? We have discovered a difference between the tried and true SMK's and the newer TMK's with notable increase in the new TMK bullet bearing surface, we are seeing an increased pressure curve over the SMK's. This pressure increase has been troublesome in my .308 Auto loader with primer extrusion and piercing issues. Just curious if anyone else is experiencing similar issues with the TMK's or any other heavy XLR type bullets on the market? Note: This is similar to primer issues more commonly discussed with 280 Rem and 6.5 Creedmore shooters running a heavier bullet.

24" Heavy SS, 10.5 twist(Bartlein), 175gr TMK, Lapua, 43.8gr Varget, CCI BR-2, 2680fps@5860ft ASL

[Eurodriver]

We used the 175gr TMKs exclusively for about a year out of a 20" Krieger .308. It really helped buck the wind and get us to 1000 out of the shorter barrel.

We thought they were great bullets, but have since consolidated to .223 for center fire.

[smihtp]

Yes... By no means am I downplaying the bullet, I absolutely love E'm and intend to continue using. I was just curious if anyone else was seeing this odd pressure curve?
My shooting altitude is 5860ft at the bench so we don't really have to push the pills as hard as the guys at Sea level would typically, I could back down to the next lowest NODE or apply a fix the Creedmoor guys use with an "small pin" Bolt modification. I really like the max range I'm at now and see no real reason (other pressure signs) to change it. I switched over to the TMK when I found my old goto Varget load was falling trans-sonic at 975yds. Not unlike yourself, I started using the new TMK's to stretch the distance a tad. This problem never presented itself with the 175 SMK's or Match Burners, only the TMK's.

[Eurodriver]

Sorry, duh, I missed the point.

The short answer is I didn't see any significant pressure curves - nothing different than SMKs. Although it does seem like it could happen because from my memory they sat deeper than the SMKs. I am at sea level though. 99% of my shooting is done at exactly 31ft above sea level. Maybe that matters? I am always pushing close to or even above max for every 308 and 223 distance load. Even with TMKs you need to or out of your 20" you will go subsonic before 1000.

[smihtp]

If I may can I ask what primer you are using in your max loads for distance? Yes they are long, I seat mine .010 off the lands, at that depth and they WILL NOT fit the magazine. Shooting a two shot/target steel match "Who cares?"
I have had trouble with both 210M's and CCI BR-2's cookie cutting. My GS did some recent extractor polishing, it didn't help the problem.
Even though we see metal extrusion into the firing pin hole on every round only about 3-4 out of fifty will actually blow back enough to pop out a nice little hole in the center of the primer cup.
I have read posts of this exact problem with people running heavier bullets in 280's and 6.5's but nothing on the .308 This new 5R BL barrel is running a tight Match chamber... it must be well polished, I've never stuck a case in it.

[markm]

We subbed them directly in place of regular SMKs and didn't notice any pressure issues with stout bolt gun loads. 210M primers and 43.8 - 44.3 gr Varget. No consideration for bullet jump as we didn't find it to be needed. (any bullet with a jump issue is Bulleta Non Grata for our purposes)

[smihtp]

43.8 Varget is also my load of choice with no pressure signs on the case or flattening of the primer(s(210M's or BR-2's)). Still no word from the GS on the bolt in question? I may have to go that alone.
Thanks again for the input.

[markm]

The thing with Varget is that lot velocities can vary wildly. I shot two different lots loaded on the same day, on the same Chargemaster. Shot both on the same gun at the same session, and the newest lot shot 60 fps slower over my magnetospeed.

I confirmed this at 1000 yards by shooting my old lot on steel, and then watching my new lot drop bullets into the dirt short of the steel. Bummer.

[HKGuns]

I've used them as direct subs for each other and not noticed anything odd or even different.

[akssdude]

Have any of you guys tried these bullets on game like deer or hogs?