16.5” 6.5 prc? build

simmonzz

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Rather than start a new thread I figured I'd ask all of your guys' opinion on the new situation. I sold the deviant barreled action because I couldn't find a magnum bolt and became set on running a magnum. I have since ordered a Tenacity with a magnum bolt should arrive tomorrow. I can order a brand new 16.5" proof carbon 6.5mm 7.5 twist for $700 shipped or I can pick up a 20" proof carbon 6.5mm 8 twist for $550 shipped. I didn't really want to run a 20" barrel because I'll have a can on it. I was pretty set on 16.5" or maybe 18".. the plan is to run 6.5prc because I think it's just gonna be the easier route considering saum brass is hard to find. 6.5 saum and 6.5 prc are the top contenders I'm looking at. Another thing I'm unsure of is if running a 16.5, 18, or 20" barrel requires a faster powder? I have no experience with these cartridges
 

rlspahn

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Rather than start a new thread I figured I'd ask all of your guys' opinion on the new situation. I sold the deviant barreled action because I couldn't find a magnum bolt and became set on running a magnum. I have since ordered a Tenacity with a magnum bolt should arrive tomorrow. I can order a brand new 16.5" proof carbon 6.5mm 7.5 twist for $700 shipped or I can pick up a 20" proof carbon 6.5mm 8 twist for $550 shipped. I didn't really want to run a 20" barrel because I'll have a can on it. I was pretty set on 16.5" or maybe 18".. the plan is to run 6.5prc because I think it's just gonna be the easier route considering saum brass is hard to find. 6.5 saum and 6.5 prc are the top contenders I'm looking at. Another thing I'm unsure of is if running a 16.5, 18, or 20" barrel requires a faster powder? I have no experience with these cartridges
Faster powder not required IMO. It may not be intuitively obvious, but it won't create greater velocity than the slower burning powder in these magnums. I recall reading a test somewhere (magazine) where they tested different powders with different barrel lengths using the same bullet - the powder that gave the highest velocity in the long barrels gave the highest velocity in the short barrels. You will end up with more muzzle flash using the slower powder, but your velocity will be higher.

The faster powders will build pressure faster, and the max load will be somewhat less than what you can achieve with a slower-burning powder. While the faster powder may provide a more complete burn in the barrel relative to the slower powder, it's still not able to generate a higher velocity.
 

simmonzz

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Faster powder not required IMO. It may not be intuitively obvious, but it won't create greater velocity than the slower burning powder in these magnums. I recall reading a test somewhere (magazine) where they tested different powders with different barrel lengths using the same bullet - the powder that gave the highest velocity in the long barrels gave the highest velocity in the short barrels. You will end up with more muzzle flash using the slower powder, but your velocity will be higher.

The faster powders will build pressure faster, and the max load will be somewhat less than what you can achieve with a slower-burning powder. While the faster powder may provide a more complete burn in the barrel relative to the slower powder, it's still not able to generate a higher velocity.
That’s case even with the lighter bullets like 124g hammer hunters or 131g hammer hunters? I hate being such an indecisive person lol it makes building these customs a pain in the *** because I always try to save money or buy stuff thru sales. I’m torn between feeling the 20” will possibly between too long with the can (suppressor is 7.5”) and I know the 16.5” will be awesome it’s just a matter of spending $150 more for the shorter tube and giving up some extra velocity. The 124s or 131s should still come out of the 16.5 pretty quick I feel like. Faster than my 6.5cm anyway
 

rlspahn

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That’s case even with the lighter bullets like 124g hammer hunters or 131g hammer hunters? I hate being such an indecisive person lol it makes building these customs a pain in the *** because I always try to save money or buy stuff thru sales. I’m torn between feeling the 20” will possibly between too long with the can (suppressor is 7.5”) and I know the 16.5” will be awesome it’s just a matter of spending $150 more for the shorter tube and giving up some extra velocity. The 124s or 131s should still come out of the 16.5 pretty quick I feel like. Faster than my 6.5cm anyway
Each bullet will be different. For a given cartridge in a given barrel length, moving to a lighter weight bullet may require a faster powder to achieve maximum velocity. I ran into this with a 7 SAUM improved. I could reach max load/pressure with H1000 and a 180 gr bullet. When I tried H1000 with a 155 gr bullet, I couldn't reach max pressure with it as I ran out of room in the case (case fill exceeded 100%) before I reached max pressure. I moved to a faster powder and was able to reach max pressure with a resulting higher velocity. There are a lot of different factors that have to be considered, each with their own impact on achieving a desired result.
 

simmonzz

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Each bullet will be different. For a given cartridge in a given barrel length, moving to a lighter weight bullet may require a faster powder to achieve maximum velocity. I ran into this with a 7 SAUM improved. I could reach max load/pressure with H1000 and a 180 gr bullet. When I tried H1000 with a 155 gr bullet, I couldn't reach max pressure with it as I ran out of room in the case (case fill exceeded 100%) before I reached max pressure. I moved to a faster powder and was able to reach max pressure with a resulting higher velocity. There are a lot of different factors that have to be considered, each with their own impact on achieving a desired result.
Understood. I feel like the typical powders used for the 140-156 range probably won’t be optimized for the 120-130 range. I talked to Steve at hammer bullets today and he said he’d never tested or shot a 16.5” rifle so he wasn’t sure what powders to recommend but it sounded like h4350-4831 would be a good range for a 20” barrel. I just was hoping more people might be able to chime in with real world data with what they’re using before I try and stock some powders I don’t have on hand because we all know powder is really hard to get and can be spendy if we do find it. I’m leaning towards going 16.5” because I know it’ll be just fine with the suppressor. 20” would probably be ok too it’s just gonna be as long as my 26” which is one of the whole reasons I’m trying to build a shorter rifle
 

JuddL

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My 2 cents that are somewhat unsolicited. Everytime I’ve bought or built a rifle a certain way to save money I’ve almost always went back and done what I wanted later. In the long run I think you’re better off to buy the 16” barrel now and be done with it. You will never know if you like it if you don’t do it and you clearly want too.

Is a 20” fine? Absolutely.

Now saying all of that….I had a 6.5saum 16” proof barrel…I really liked that rig w/ 123 Scenars sitting on top of MR4000, speed was 3040FPS. I’m sort of answering your other question is why I’m telling you this…yes, when going to that short of a barrel I do like to go to a slightly faster burn. A lot of guys don’t and have no problems. H1000 is the standard with the 6.5saum and I’ve never tried it in mine.

Next thing…I got tired of hearing a buddy chirp in my ear about wanting the rifle so he now owns it. I’m going to build another and it’ll be a 20-22” but not because I didn’t like the short one…but because I want to try and shoot the 156’s that everyone is going crazy over.

Good luck with whatever you do and I hope this rambling helped you somehow.
 

North Idaho Hunter

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I would most definitely go 6.5 saum! We've shot both PRC & SAUM, the saum just checks all the boxes for us - also, you should note, in reality Saum brass is easier to find in this current climate!

20'' would give optimal velocity in your situation however depending on the can you run you may end up with overall length issues from your intended target length.

This is all in good fun! Don't sweat $150 on a potential life long investment!
 

simmonzz

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My 2 cents that are somewhat unsolicited. Everytime I’ve bought or built a rifle a certain way to save money I’ve almost always went back and done what I wanted later. In the long run I think you’re better off to buy the 16” barrel now and be done with it. You will never know if you like it if you don’t do it and you clearly want too.

Is a 20” fine? Absolutely.

Now saying all of that….I had a 6.5saum 16” proof barrel…I really liked that rig w/ 123 Scenars sitting on top of MR4000, speed was 3040FPS. I’m sort of answering your other question is why I’m telling you this…yes, when going to that short of a barrel I do like to go to a slightly faster burn. A lot of guys don’t and have no problems. H1000 is the standard with the 6.5saum and I’ve never tried it in mine.

Next thing…I got tired of hearing a buddy chirp in my ear about wanting the rifle so he now owns it. I’m going to build another and it’ll be a 20-22” but not because I didn’t like the short one…but because I want to try and shoot the 156’s that everyone is going crazy over.

Good luck with whatever you do and I hope this rambling helped you somehow.
I would most definitely go 6.5 saum! We've shot both PRC & SAUM, the saum just checks all the boxes for us - also, you should note, in reality Saum brass is easier to find in this current climate!

20'' would give optimal velocity in your situation however depending on the can you run you may end up with overall length issues from your intended target length.

This is all in good fun! Don't sweat $150 on a potential life long investment!

Awesome thanks guys. I'm definitely not opposed to 6.5 saum and in a way a little more inclined to it because i can squeeze out a little more velocity but finding saum brass does seem to be harder than prc brass. both of which arent easy right now lol unless im looking in the wrong spots. any real difference in 6.5 saum and 6.5 gap4s?
 

North Idaho Hunter

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No difference between saum and gap4s. You will get a boost in velocity going up to SAUM vs PRC.

Also - Keep an eye out for prime factory 6.5 SAUM ammunition.

You can easily neck down 300/7 saum brass. Skim Inside (to prevent donuts) & outside Neck turning is recommended here when necking down.
 

simmonzz

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No difference between saum and gap4s. You will get a boost in velocity going up to SAUM vs PRC.

Also - Keep an eye out for prime factory 6.5 SAUM ammunition.

You can easily neck down 300/7 saum brass. Skim Inside (to prevent donuts) & outside Neck turning is recommended here when necking down.
I'd rather not have to neck down if i dont have to. is prime ammo loaded pretty hot or would i still benefit from reloading? I dont know all of the makers of saum brass im assuming adg is king? ive had really good luck with lapua brass for my 300 norma but im not sure they do saum brass or not off the top of my head
 

North Idaho Hunter

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ADG is right there with lapua. We use both exclusively. Prime has normally loaded with NORMA brass in past.

Prime ammunition in stock ready to ship -https://www.targetsportsusa.com/prime-ammunition-6-5-remington-saum-4s-ammo-142-grain-otm-match-plus-7528240020-p-109362.aspx

We "should" have a large shipment of 6.5 saum adg brass by early 2022.
 

simmonzz

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ADG is right there with lapua. We use both exclusively. Prime has normally loaded with NORMA brass in past.

We "should" have a large shipment of 6.5 saum adg brass by early 2022.
**** thats a ways away lol id be so sad if i had a complete rifle i couldnt shoot due to brass delays lol
 

simmonzz

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Got pretty much everything for this new build. Really hoping it works out like I anticipate. Doesn’t sound like very many people have built a 16.5” 6.5 saum. The barrel is a 7.5 twist so I’m planning on shooting 124gr hammers or 131 hammers. I’d like to be around 3050fps
 

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