December $487 prefit group buy, several barrels are a go

[Speaks]

Hey guys looking for some advice here. I keep toying with ordering a 6UM 40.

Two questions -

1 - Assume since its only offered in 20 that gives meaningful performance gains over something like at 18?

2 - If I have a 6CM and a 6.5 PRC is there a real meaningful gain to be had here? I would either be barreling the PRC or I do have another action I could use but UM seems like a pretty direct replacement for it. It looks like some small performance gain and a small improvement in recoil but not a game changer on either. Trade off is loosing access to decent factory ammo, the 147 eldm factory loads are pretty good through my PRC.

I keep debating going down that rabbit hole vs just getting an extra barrel and ammo for the 6CM and shooting the shit out of it (and yes I have a 223 trainer).

 

[hereinaz]

Hey guys looking for some advice here. I keep toying with ordering a 6UM 40.

Two questions -

1 - Assume since its only offered in 20 that gives meaningful performance gains over something like at 18?

2 - If I have a 6CM and a 6.5 PRC is there a real meaningful gain to be had here? I would either be barreling the PRC or I do have another action I could use but UM seems like a pretty direct replacement for it. It looks like some small performance gain and a small improvement in recoil but not a game changer on either. Trade off is loosing access to decent factory ammo, the 147 eldm factory loads are pretty good through my PRC.

I keep debating going down that rabbit hole vs just getting an extra barrel and ammo for the 6CM and shooting the shit out of it (and yes I have a 223 trainer).

If you keep the 6.5 barrel, it’s always an option.

How big the differences are, always depends on how you weigh the factors. Changing all the time isn’t good.

Shooting practice always trumps the gains by the marginal improvements in performance. You would become a better rifleman only with rounds down range. I say shooting out a barrel will do more than switching what you have.

 

[TheViking]

Hey guys looking for some advice here. I keep toying with ordering a 6UM 40.

Two questions -

1 - Assume since its only offered in 20 that gives meaningful performance gains over something like at 18?

2 - If I have a 6CM and a 6.5 PRC is there a real meaningful gain to be had here? I would either be barreling the PRC or I do have another action I could use but UM seems like a pretty direct replacement for it. It looks like some small performance gain and a small improvement in recoil but not a game changer on either. Trade off is loosing access to decent factory ammo, the 147 eldm factory loads are pretty good through my PRC.

I keep debating going down that rabbit hole vs just getting an extra barrel and ammo for the 6CM and shooting the shit out of it (and yes I have a 223 trainer).

You have to do some math and figure all this out. On average you lose 25-30fps per inch of barrel. Take your approximate velocity, use box if you’re shooting factory. Then subtract 25-30fps per inch from 24” (typical test barrel length). Find the BC (ballistic coefficient) of the specific bullet you’re using. Use a ballistic calculator with environmental (elevation, temp, etc). Keep your bullet above 1800fps at impact, I personally do 2000.

6.5 PRC will give you +/- 200fps over 6.5 CM, which will you give you about 200 more yards of range.

 

[JoeK]

If you keep the 6.5 barrel, it’s always an option.

How big the differences are, always depends on how you weigh the factors. Changing all the time isn’t good.

Shooting practice always trumps the gains by the marginal improvements in performance. You would become a better rifleman only with rounds down range. I say shooting out a barrel will do more than switching what you have.

Very well put ^

 

[walk2112]

I thought the tikka COAL limitations would prevent the 257 w/heavy high BC bullets? Or just if need the UM bottom metal and magazine to work? I also thought I read that it would require milling a groove in the feedramp /receiver…?

Yep, would want one of the longer magazine options from the aftermarket to really seat the bullets where they oughta be.
I don’t know about milling a groove receiver, thought that was for other actions, but could be wrong as I haven’t tried one.

 

[Speaks]

If you keep the 6.5 barrel, it’s always an option.

How big the differences are, always depends on how you weigh the factors. Changing all the time isn’t good.

Shooting practice always trumps the gains by the marginal improvements in performance. You would become a better rifleman only with rounds down range. I say shooting out a barrel will do more than switching what you have.

Thanks I think your right. The shiny new better thing is always tempting.

Will just shoot the 223 and the new 22CM and 6CM barrels a bunch and if I get to where I actually need more than that to kill actual animals will consider whether to keep the PRC or swap it to a UM.

 

[AZ_Hunter]

Would anyone else be interested in either a 6-284 or 6mm Rem AI? Something to maximize a 6mm with a std bolt face.

 

[wyosam]

Would anyone else be interested in either a 6-284 or 6mm Rem AI? Something to maximize a 6mm with a std bolt face.

Yep. The 6rem would be great, except brass options suck. 6-284 has good brass available, and the 284 case works great in Tikkas. I’d buy a 6-284 today.


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[Speaks]

What torque are you all using to install these? Old barrel came right of but just wanted to confirm before putting the new one on.

 

[The Guide]

What torque are you all using to install these? Old barrel came right of but just wanted to confirm before putting the new one on.

80-100 ft/lbs using an internal action wrench and a torque wrench.

Jay

 

[wyosam]

What torque are you all using to install these? Old barrel came right of but just wanted to confirm before putting the new one on.

I do 80. I know a lot of folks cranks them down gorilla tight, but I’ve never had an issue.


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[Speaks]

Received my barrel, factory one came off with no real fuss and new one went on easily and go/no-go gauges say I am all set. Fun little Saturday project and excited to get it to the range this week.

Thanks for doing the sale, super excited to have a 6CM in the lineup.

 

[TimberHunter]

Received my barrel, factory one came off with no real fuss and new one went on easily and go/no-go gauges say I am all set. Fun little Saturday project and excited to get it to the range this week.

Thanks for doing the sale, super excited to have a 6CM in the lineup.

View attachment 984562

What vise/wrench do you use? Factory barrel coming right off is unheard of from what I’ve read


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[amassi]

What vise/wrench do you use? Factory barrel coming right off is unheard of from what I’ve read


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Eh it’s not as hard as is often made out, they have antiseize on the threads from the factory
Factory new rifles that have only been test fired, pop right off.


A T3 ctr in 308 with ~8,000 rounds on it has been the hardest yet but the internal wrench held. The antiseize on the threads was hard and dry.

I use an internal wrench from bugholes and bench mounted vice from mech gear
I’m over 100 with that combo and haven’t had to use a dead blow hammer or anything just a 36” breaker bar and piece of pipe
The vice is worn out though so It’s time to replace it.


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[amassi]

Received my barrel, factory one came off with no real fuss and new one went on easily and go/no-go gauges say I am all set. Fun little Saturday project and excited to get it to the range this week.

Thanks for doing the sale, super excited to have a 6CM in the lineup.

View attachment 984562

What scope covers are those?


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[TimberHunter]

Eh it’s not as hard as is often made out, they have antiseize on the threads from the factory
Factory new rifles that have only been test fired, pop right off.


A T3 ctr in 308 with ~8,000 rounds on it has been the hardest yet but the internal wrench held. The antiseize on the threads was hard and dry.

I use an internal wrench from bugholes and bench mounted vice from mech gear
I’m over 100 with that combo and haven’t had to use a dead blow hammer or anything just a 36” breaker bar and piece of pipe
The vice is worn out though so It’s time to replace it.


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Good to know. You buying another one of those vises or a different one?

No external wrench huh?


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[amassi]

Good to know. You buying another one of those vises or a different one?

No external wrench huh?


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I’ll get the same one, it works good for the different cylinder sizes without needing shims
All internal for me, but I have an external because I kept reading horror stories about breaking wrenches but it’s still in the box.
Knock on wood, I’m sure I’ll break that bughole wrench now


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[Speaks]

What vise/wrench do you use? Factory barrel coming right off is unheard of from what I’ve read


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The short barrel customs bravo with the tikka sporter bushings. It was on sale last week super cheap. I used the wheeler external mauser wrench and a short cheater bar to take it off and the sbc internal wrench to put it back on. No heat, freezing, solvents, or hammers required. Honestly dont think I would have needed the cheater bar. First pull it spun so I cranked the vice tighter, next pull it popped right off.

Wasnt a totally new action but had pretty limited shots on it.

 

[Speaks]

What scope covers are those?


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Scope bumpers, trying them for the first time. Kind of overpriced but way less fiddly than the flip open ones.

 

[Ibex]

I have had good luck with sac vice and wheeler external action wrench, setup where I can put reasonable downward force on wrench with just body weight and hit with dead blow hammer. I’ve done 4 and they spin off easy.