Sierra Heavy TMK 6MM Testing

[wind gypsy]

The latest S2H podcast Jake said they’ve got a lot of returns on the ammo. He said it’s for shooting in hunting weather, not in the summer.

Well, that is.. unintelligent.

 

[Frozenlead]

I have had really good customer service from UM in the past and I don't have any doubts that will be the case here. I did some more hillbilly math with my grain scale and I am finding that there appears to be about 43-44 grains of h4350 in these loads. Those figures are not accounting for any powder residue still attached to the brass, so it could be higher than that.

In terms of getting the TMK to shoot, would dialing back the velocity a bit potentially help? Or is it more likely that the rifle doesn't like that bullet?

As mentioned by a few 43-44gr is hot for a .243. In GRT with the 108eldms and 43grs you’re sitting near 70k psi and 2900fps. So over pressure for sure and the brass is showing all the signs.
Dialing it back a bunch would probably help.

 

[mlevimadden]

The latest S2H podcast Jake said they’ve got a lot of returns on the ammo. He said it’s for shooting in hunting weather, not in the summer.

Hunting in wet conditions is just as likely to produce the same pressure issues as hot and dry summer conditions. I will happily trade 50-100 fps of muzzle velocity to not be popping primers or having ejection issues, especially in a field rifle where reliability of feed/function is paramount.

 

[Ryan Avery]

Trying to make custom ammo without having the rifle is a mess for everyone involved. I’ve told Jake many times that I won’t do it unless I can do full-load development with the actual rifle. Without it, the results are unpredictable. If the rounds are too slow, they get sent back. If they aren’t accurate, they get sent back. If they’re over-pressured, they get sent back. That’s why most companies avoid this, even with what’s supposed to be a "standard load".

 

[mtnbound]

The latest S2H podcast Jake said they’ve got a lot of returns on the ammo. He said it’s for shooting in hunting weather, not in the summer.

This is talked about starting at 7:49 minute mark of the podcast.

Jake said they have had "some returns over the years", not "a lot" of returns, and it was related to the Mayhem line, which is their high-performance ammo intended for hunting. He did say it's not designed for hunting in 110-degree temps.

 

[huntnful]

Are you having any issues with bullets staying seated being fed from a mag at 2.92" COAL? Not that 6CM is a heavy hitter, but my 116 TMKs showed up yesterday, and I'm getting very similar measurements to yours for jam in a SAAMI chamber. Looks like you're loading roughly 0.13" of bearing surface into the neck with a 0.020" jump. I was planning to start at 2.90" COAL, but it's definitely less bearing surface/case neck engagement than I have done in the past.

I single fed 10 and then mag fed 10. Couldn’t see any accuracy difference worth noting. So must not be having too much deflection on the bullet when chambering from the mag and hitting the feed ramp

 

[walkingduckwaterfowl]

@Ryan Avery navery Yeah, I agree with you totally. For me, I am not at all concerned about speed. If I was getting 2750 with access to better bullets in the .243 I would be a happy camper. It's just something I can't buy anywhere else so I figured I would give it a try. If I had a better understanding and knew it was safe for me and my equipment I would just shoot em up. I have spent probably close to 2k with UM on scope rings, ammo, and a rokstok and have had nothing but awesome customer service to date.

My question was about if dialing back the powder for the TMK's would be likely to produce better accuracy, or at least likely enough to feel good about making another purchase. IIRC earlier in the thread guys were talking about how a 6BR just shoots everything and thought maybe that had to do with the less velocity?

 

[wind gypsy]

@Ryan Avery navery Yeah, I agree with you totally. For me, I am not at all concerned about speed. If I was getting 2750 with access to better bullets in the .243 I would be a happy camper. It's just something I can't buy anywhere else so I figured I would give it a try. If I had a better understanding and knew it was safe for me and my equipment I would just shoot em up. I have spent probably close to 2k with UM on scope rings, ammo, and a rokstok and have had nothing but awesome customer service to date.

My question was about if dialing back the powder for the TMK's would be likely to produce better accuracy, or at least likely enough to feel good about making another purchase. IIRC earlier in the thread guys were talking about how a 6BR just shoots everything and thought maybe that had to do with the less velocity?

It's more than just low velocity in the BR case. I dont know exactly what the sauce is but generally those modest sized cases are less finicky. Throw in well designed chamber specs and premium brass and they shoot.

Impossible to say if the 107 TMKs would shoot at a lower pressure/velocity without trying in your gun.

Trying to make custom ammo without having the rifle is a mess for everyone involved. I’ve told Jake many times that I won’t do it unless I can do full-load development with the actual rifle. Without it, the results are unpredictable. If the rounds are too slow, they get sent back. If they aren’t accurate, they get sent back. If they’re over-pressured, they get sent back. That’s why most companies avoid this, even with what’s supposed to be a "standard load".

Is it custom ammo though or is it just standard ammo with more attention taken during the loading process? I cant wrap my head around putting 42.7+ gr H4350 behind a 108 in a 243 and selling as standard ammo. Put 41 grains in and people will be happy with a source for heavy pill 243 ammo at reasonable velocities.
Edit: listened to the referenced segment of the podcast. The context in regards to "custom load request" and Mayhem line make more sense now because that was the question Avery asked him. Pretty "bold" to load stuff that hot still IMO but the context of temp seemed less dumb than it did in this thread. He said "It's not designed to be shot at 110 degrees".

 

[WyldGoose]

This is talked about starting at 7:49 minute mark of the podcast.

Jake said they have had "some returns over the years", not "a lot" of returns, and it was related to the Mayhem line, which is their high-performance ammo intended for hunting. He did say it's not designed for hunting in 110-degree temps.

Thanks for a more precise quote/timestamp, much more helpful than my post. I listened last week and didn’t catch they were talking about a specific line of ammo. Just that Jake implied it wasn’t uncommon to see returns and Ryan laughing his nuts off.

 

[Treelineasassin]

The latest S2H podcast Jake said they’ve got a lot of returns on the ammo. He said it’s for shooting in hunting weather, not in the summer.

Are they loading ball powder?! That's a poor excuse. It's still typical hunting weather in most the USA right now, spring VS fall, what's the difference? If it's too hot now, it's gonna be hot in October or November.

 

[walkingduckwaterfowl]

I would say it qualifies as custom ammo in the sense that I asked for and got what I wanted for bullet/cartridge. Not many other places to buy that especially the new hot stuff like the TMK. It comes in a non standard cool reusable box and it even smells good when you open it. They advertised a long lead time and the ammo showed up very quickly. Literally everything about it was awesome until things started to feel unsafe.

 

[dårlig jeger]

116s in stock at Midway

Sierra Tipped MatchKing 6.5mm, 264 Cal (264 Diameter) Bullets 107

MatchKing rifle bullets are super-accurate bullets with very thin jackets and are held to exacting tolerances in diameter and weight. Their accuracy has...

www.midwayusa.com

 

[huntnful]

I shot a short throat 6 creed barrel for a season of PRS. It was the most accurate 6 creed out of a few barrels I had by a long shot.

Good to hear!

I just don’t see the need for .183 FB other than for the 108 ELDM. None of the Berger’s or new TMK’s need it. Not that things shoot poorly, I just seem to have better precision with bullets close to the lands and adequately in the case neck. Not one or the other.

 

[Jordan Smith]

I shot a short throat 6 creed barrel for a season of PRS. It was the most accurate 6 creed out of a few barrels I had by a long shot.

Same here. I generally spec a shorter-than-SAAMI throat in the 6CM.

 

[Formidilosus]

My question was about if dialing back the powder for the TMK's would be likely to produce better accuracy, or at least likely enough to feel good about making another purchase. IIRC earlier in the thread guys were talking about how a 6BR just shoots everything and thought maybe that had to do with the less velocity?

I’ve yet to see a Tikka 243 1:8” twist not shoot the 116’s well. The “Mayham” ammo is silly. Send it back, and request normal ammo, or “Forms” load from Blaine. I’ll get them what it should be.

 

[Jordan Smith]

Good to hear!

I just don’t see the need for .183 FB other than for the 108 ELDM. None of the Berger’s or new TMK’s need it. Not that things shoot poorly, I just seem to have better precision with bullets close to the lands and adequately in the case neck. Not one or the other.

A 0.183 FB is certainly not needed for the 108 ELD-M, either.

 

[walkingduckwaterfowl]

I’ve yet to see a Tikka 243 1:8” twist not shoot the 116’s well. The “Mayham” ammo is silly. Send it back, and request normal ammo, or “Forms” load from Blaine. I’ll get them what it should be.

UM is taking care of me l. I appreciate you letting them know! I will buy a bunch

 

[Jimbee]

I’ve yet to see a Tikka 243 1:8” twist not shoot the 116’s well. The “Mayham” ammo is silly. Send it back, and request normal ammo, or “Forms” load from Blaine. I’ll get them what it should be.

Care to share that load info?