6.5 PRC Build on Sportsman 78 Action Questions

[Marshfly]

I've had this Sportsman 78 in 270 Win since I was a teenager. It was outfitted with a Zeiss Conquest and a nice BDL stock for eastern whitetail hunting since we lived in Louisiana.

Since moving to Montana I've been changing things to make it more suitable for western hunting.

Peak 44 Blacktooth stock to keep from destroying the fine finish on the BDL stock and save a full pound on the rifle.
Trijicon Tenmile 3-18x44 because it works...LOL.

The rifle is awesome as is. 6# flat bare and 7.75# full up with the scope. The only thing holding me back is that with factory ammo this particular rifle will only really group the Federal and Barnes loaded TSX and TTSX rounds acceptably. I really want to move away from copper bullets but after trying a ton of other ammo this barrel just won't do it.

So having a conversation with my smith that also specializes in custom builds I came upon the idea to have him to some work to the action, truing and ceracoat, and rebarrel this in a short 6.5 PRC for suppressor use with the goal of shooting the 156 Barnes EOL.

The plan is a Lilja barrel (that's what he likes and is comfortable with) at 18 inches topped with a TBAX Ultra 7.There will also be a little custom work on the bolt and receiver to make this a true custom since we are doing all this work.

My questions are what contour barrel? What threading on the barrel? What twist rate? What mounting configuration do I order this Ultra 7 to accomplish my goals?

Also any other ideas are much appreciated.

 

[Marshfly]

Adding in that I'm essentially trying to build something similar to a Seeking Havoc Element. If I didn't own this already I'd just buy that. I'm not interested in selling this and I really, really like this stock so this is what I've decided to do.

 

[amassi]

Lila #4 will have plenty of shoulder at 18” for your can
A #3 might but I’d check if he or lilia has one they can measure the od @ 18”


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[amassi]

Also what magazine inlet in the stock?
If you want to stay bdl you should look at a Wyatt’s center feed
If you want a magazine unknown munitions has a great dbm


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[Marshfly]

Lila #4 will have plenty of shoulder at 18” for your can
A #3 might but I’d check if he or lilia has one they can measure the od @ 18”


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I wonder what the weight is of this factory barrel. Trying to keep at the same weight or even shed some.

Edit: Just measured the factory barrel at 0.653 at the 22" muzzle so slightly thicker than the Lilja #4. That could work. Could even flute it to cut a little weight on top.

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[Marshfly]

Also what magazine inlet in the stock?
If you want to stay bdl you should look at a Wyatt’s center feed
If you want a magazine unknown munitions has a great dbm


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This stock is inletted for the factory Remington floor plate. May replace with a Hawkins so I can have it ceracoated to match the action during the build. I have zero desire for a removable magazine on a hunting rifle. Just something to lose IMHO. I know some like them though.

 

[Mountainrancher]

I’m unfamiliar with the action you’re using but I’m assuming your smith can open up/change the bolt to be a magnum bolt face?

 

[amassi]

I’m unfamiliar with the action you’re using but I’m assuming your smith can open up/change the bolt to be a magnum bolt face?

It’s a model 700 that was sold at big box stores like sears and K-mart.


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[amassi]

This stock is inletted for the factory Remington floor plate. May replace with a Hawkins so I can have it ceracoated to match the action during the build. I have zero desire for a removable magazine on a hunting rifle. Just something to lose IMHO. I know some like them though.

Agree on the magazine issue, the exception being sako. Those magazines can’t fall out on their own since you have to depress the mag and hit the release. Either way a bdl bottom would feed best with the Wyatt’s center feed. If you stay staggered you smith will likely need to do some work to get it to feed right


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[Marshfly]

I’m unfamiliar with the action you’re using but I’m assuming your smith can open up/change the bolt to be a magnum bolt face?

It’s a 700 that came with a basic wood stock and the action and barrel were not gloss. Same as any other 700 except for the finish. Lots of people love the actions as a base for custom builds.


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[MHWASH]

I'm in the same boat as you, except I'm going 7mm. I have brass for the 7SAUM and 280AI. My concern is feeding a short action cartridge out of a long action. Should talk to a smith but I haven't yet.

I received my 78 .270 34 years ago. Have used it on multiple deer and a couple of bear.

 

[amassi]

I'm in the same boat as you, except I'm going 7mm. I have brass for the 7SAUM and 280AI. My concern is feeding a short action cartridge out of a long action. Should talk to a smith but I haven't yet.

I received my 78 .270 34 years ago. Have used it on multiple deer and a couple of bear.

Short out of a long is a non issue, my first 7 saum fed from a long action 700. The only feeding issue was from the staggered magazine. Wyatt’s center feed fixes that
You can also get internal magazines that are blocked at the rear to shorten mag length( weatherby does this with the 257,270&7mm since all 9 lug wby actions are 3.6”)


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[Marshfly]

I'm in the same boat as you, except I'm going 7mm. I have brass for the 7SAUM and 280AI. My concern is feeding a short action cartridge out of a long action. Should talk to a smith but I haven't yet.

I received my 78 .270 34 years ago. Have used it on multiple deer and a couple of bear.

My smith told me he doesn’t build 6.5PRC on short actions anymore due to feeding issues.

That might answer your dilemma. Haha.


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[Marshfly]

Short out of a long is a non issue, my first 7 saum fed from a long action 700. The only feeding issue was from the staggered magazine. Wyatt’s center feed fixes that
You can also get internal magazines that are blocked at the rear to shorten mag length( weatherby does this with the 257,270&7mm since all 9 lug wby actions are 3.6”)


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Do you know what the round count is for the Wyatt center feed with the PRC?


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[amassi]

Do you know what the round count is for the Wyatt center feed with the PRC?


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Center feed will be 2, staggered 3.


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[TaperPin]

As much as I love the 270, the 6.5 prc is a step up. You’ll love the extra accuracy of a new barrel. A #3 contour seems a little heavy for a mountain gun, but not bad for an average weight western rifle.

I like keeping old guns and having new barrels screwed on. Sounds like you’ll have a great setup when it’s finished. It’s funny, I had totally forgotten the sportsman 78 even existed.

 

[Marshfly]

Yeah. The smith suggested a #2 contour when we chatted a while back. I need to go have a sit-down with him soon and hammer this out so we can start getting parts ordered.
My biggest unknown is what barrel contour to order to match with what suppressor adapter while keeping my goal of light weight in mind. I'd like this rifle to end up the same weight as it is currently but with the TBAC Ultra 7 included.

 

[amassi]

Yeah. The smith suggested a #2 contour when we chatted a while back. I need to go have a sit-down with him soon and hammer this out so we can start getting parts ordered.
My biggest unknown is what barrel contour to order to match with what suppressor adapter while keeping my goal of light weight in mind. I'd like this rifle to end up the same weight as it is currently but with the TBAC Ultra 7 included.

You can always go a lighter contour with a shoulder for your suppressor- meaning the shoulder is contoured onto the muzzle not a thread on.


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[Marshfly]

I honestly have to wonder if it really matters. TBAC makes CB muzzle devices or adapters for everything from 1/2-28 on up so I can just use whatever really.

 

[Oaks]

Any update on your build?