Caliber ideas for new ACC build

[Cardboard Assassin]

Howdy folks!

I picked up an MDT ACC (Rem 700 SA footprint) in the Black Friday sales and want everyones thoughts on the pros / cons of various calibers. I dont have an action for it yet as I want to decide on the caliber first (that will be another thread although from what I can tell any SA action will cover any of the calibers I am considering)

Up to this point the only long range gun I own is a Ruger Precision in 6.5 CM. Its served me well and is probably due a new barrel. I had the opportunity to go shoot with the local F Class guys and I used the Ruger.

This will be my first precision build and I would like to use it in PRS and F Class if that is possible. Looking at the F class rules this would mean either building a 223 or going Open, and removing the brake for matches (then reinstalling it for PRS / everything else). I'll check with my local club regarding their thoughts on using a mag fed gun but they never mentioned the magazine when I was there (I actually saw the main organizer using a mag fed ACC for a bit). I know they dont like brakes hence my idea to remove / reinstall as required.

A 223 would be an excellent trainer rifle and I'm guessing would get long barrel life. Should be cheap to run (I reload) too. I could also use this in the Sniper section of local service rifle competitions.

It seems all the serious competitions in PRS are using a 6mm of some fashion due to the flat shooting characteristics and low recoil making it easy to spot hits / misses. I have done a lot of research and they all seem crazy accurate. Some other stuff I keep hearing is that 6 Dasher is naturally easy to load for but takes some fiddling to get it to feed reliably from magazines due to its short length. This got me looking at 6XC and 6GT which seem to not have feeding issues. Do these calibers have any issues I should be aware of? Any others I should look at?

It seems 6mms are hard on barrels - what is realistic barrel life of these calibers? Are some better than others? I have mentioned 6mm Creedmoor as it seems to have very short barrel life.

As an outside bet what is everyones thoughts on 22 Creedmoor? Ive seen one in action and it looked like an awesome round. Crazy accurate using the 95Gr Sierra Match Kings. Not sure how it would compare to the 6mm at longer ranges and what barrel life to expect? I imagine cost to run would be similar?

As I already have a 6.5 CM I didnt really consider this round. I will rebarrel the Ruger and keep using it as I like it and have tailored it some (Magpul PRS stock, Timmy trigger etc)

 

[DaChank]

For a practice gun I would go 308. Long barrel life and it will help you practice recoil control/wind calls.

For your main caliber personally I would take a look at 6.5x47 Lapua if you reload. Apparently really easy to develop a load.

 

[phlegethon]

With the 6mm cartridges there is a continuum, where the faster they are, the more finicky to load and the shorter the barrel life. You can kind of pick where you want to be along the spectrum: 6 BR -> 6 BRA -> 6 Dasher -> 6 GT -> 6x47L -> 6 CM. That being said, 6 Creedmoor isn't that hard to load for if you want PRS level accuracy. And it's often said that if you are worried about barrel life, you probably aren't shooting enough that you should worry about it.

Yes, you will probably have to use either a mag kit or MDT's BR mags if you go with one of those cartridges (I've had great results with the MDT mags but everyone's experience varies).

If you are starting out in this then you aren't going to be winning matches and I wouldn't worry too much about classification in F-open or whatever. If I were you I'd probably go with 6 BR or BRA for the crazy inherent accuracy. Try the MDT mags.

 

[Cardboard Assassin]

With the 6mm cartridges there is a continuum, where the faster they are, the more finicky to load and the shorter the barrel life. You can kind of pick where you want to be along the spectrum: 6 BR -> 6 BRA -> 6 Dasher -> 6 GT -> 6x47L -> 6 CM. That being said, 6 Creedmoor isn't that hard to load for if you want PRS level accuracy. And it's often said that if you are worried about barrel life, you probably aren't shooting enough that you should worry about it.

Yes, you will probably have to use either a mag kit or MDT's BR mags if you go with one of those cartridges (I've had great results with the MDT mags but everyone's experience varies).

If you are starting out in this then you aren't going to be winning matches and I wouldn't worry too much about classification in F-open or whatever. If I were you I'd probably go with 6 BR or BRA for the crazy inherent accuracy. Try the MDT mags.

Thank you, that is a good explanation. So to summarize, the fastest / flattest shooting rifles (desirable for competition) are harder to load for and have shorter barrel life. Sounds logical.

What are folks getting for round counts from their 6mm barrels? 2000? Thats the kind of numbers I have been seeing.

Sounds like 6BR or 6BRA would be good bets to start. Out of curiosity where does 6XC sit in the spectrum?

Ive been very impressed with the MDT gear to date and will indeed try their mags.

 

[Cardboard Assassin]

For a practice gun I would go 308. Long barrel life and it will help you practice recoil control/wind calls.

For your main caliber personally I would take a look at 6.5x47 Lapua if you reload. Apparently really easy to develop a load.

I didnt consider 308 as its not unlike my 6.5CM and I could run 223 for less cash (I'm already setup to reload 223).

I know it wont be as competitive but I could shoot it lots then rebarrel into something more competitive. With 223 I can also do lots of local service rifle competitions (sniper division).

 

[phlegethon]

What are folks getting for round counts from their 6mm barrels? 2000? Thats the kind of numbers I have been seeing.

Sounds like 6BR or 6BRA would be good bets to start. Out of curiosity where does 6XC sit in the spectrum?

I've heard as low as 1000-1500 rounds for Creedmoor and as high as 2500-3000 for BR. There will be a lot of variation there.

6 XC has a case capacity of 50 grains H20, versus 51 for 6 Creedmoor, so they ought to be fairly similar in theory. I have no experience with 6 XC.

 

[Cardboard Assassin]

I've heard as low as 1000-1500 rounds for Creedmoor and as high as 2500-3000 for BR. There will be a lot of variation there.

6 XC has a case capacity of 50 grains H20, versus 51 for 6 Creedmoor, so they ought to be fairly similar in theory. I have no experience with 6 XC.

Sounds like another reason to go 6BR.......

So how does 6BR do out to 1000? Ive just read a thread on the forum where someone was in a similar position to me but only wanted to shoot to 600 and pretty much everyone said the 6BR was the best fit but is that still the case if going to 1000 yards?

Has anyone any experience of the 22 Creedmoor and how it compares to the 6mms? I'm guessing the 6mm punches through wind better?

I have also read about 22BR - do these work the same as the 6mm variants - ie the 22 Creedmoor is faster / better but at the cost of barrel life and the slower 22BR is easier / less fussy to load for?

 

[phlegethon]

Sounds like another reason to go 6BR.......

So how does 6BR do out to 1000? Ive just read a thread on the forum where someone was in a similar position to me but only wanted to shoot to 600 and pretty much everyone said the 6BR was the best fit but is that still the case if going to 1000 yards?

Has anyone any experience of the 22 Creedmoor and how it compares to the 6mms? I'm guessing the 6mm punches through wind better?

I have also read about 22BR - do these work the same as the 6mm variants - ie the 22 Creedmoor is faster / better but at the cost of barrel life and the slower 22BR is easier / less fussy to load for?

There is only about 150 fps difference between BR and BRA, if that. There's not going to be a huge difference between any of these cartridges at 1000 yards in terms of wind drift. Play around with this calculator if you want to see for yourself:

Bullet Ballistics Comparison Calculator

A ballistics calculator for comparing wind and drop performance of two bullets.

bisonballistics.com

As for 22s, I think the big disadvantage there is that it becomes harder to spot impacts because it is such a light bullet. This is probably why the 6mm dominates these distances—it's just heavy enough to see most impacts but light enough to have controllable recoil.

I think, as someone who is not there yet, that most people will take a couple years in PRS, if they are fairly dedicated, to get to the point that the cartridge is making a real difference in their scores. I have too many barrels in too many cartridges because I like to play around with this stuff, but I guarantee I'd be a way better shooter now if I'd never started reloading and just bought five 6 CM barrels and a bunch of factory ammo when I was starting out.

 

[Cardboard Assassin]

Are all 6mms using around the same weight of bullet (100 - 110gr from what I'm seeing)? Even the slower 6BRs? Or do lighter bullets work best in them?

I looked at what most 6BRs were using for powder and it seems like Varget is the go to. Varget is a great powder but hard to weight consistently in my experience, thats why I switched to 8208 XBR for my semis.

Does 8208 or even H4350 work for 6BR (or any of the 6mms for that matter?) as I have tons of each.

 

[Delicatessen]

I am not doing either so not in the weeds of the rules but you may want to consider something like a 25 creed or similar. Less recoil than some for prs and better wind bucking for f class. Also the area 419 hellfire would be your friend for removing and reinstalling the muzzle device so you can easily do whatever (mine is repeatable between suppressor and break). I tend to like the 7mm for general purposes but that’s probably too much recoil for prs.

 

[lvmike]

I've heard as low as 1000-1500 rounds for Creedmoor and as high as 2500-3000 for BR. There will be a lot of variation there.

6 XC has a case capacity of 50 grains H20, versus 51 for 6 Creedmoor, so they ought to be fairly similar in theory. I have no experience with 6 XC.

I've shot 6XC. It was pretty easy to load for. Unfortunately I'm hearing things from people I know still shooting it that normas brass is not very consistent, some lots have been good others all over the place.

6CM isnt bad either. Though a big part of why for me is I tend to use bullet that are jump tolerant and easier to load for. So I'd choose Berger hybrids or even Sierra 107 SMKs over choices like DTACs or newer projectiles with less available data.

 

[paulwardd]

Does 8208 or even H4350 work for 6BR (or any of the 6mms for that matter?) as I have tons of each.

Someone else with more experience could give you a better answer, but with that being said it seems like 8208 falls in about the range of powders used for 6mm's, but I don't know how popular of a choice it is. H4350 is a much slower powder than what you'd use for most, the only ones I know where you use slow powders like it are 6x47 and 6 creedmoor. From what I see 4350 is the most typical choice for those two, all others using faster powders similar to Varget. Hope this helps

 

[Eric_F]

Varget, 8208XBR, and H4985 all work well in my 6 BRA, and the latter two meter well for me. Some guys at Accurate Shooter have used H4350 in BRA and Dasher but you need a tall drop tube to stuff all that in to make it worthwhile.

 

[Cardboard Assassin]

Varget, 8208XBR, and H4985 all work well in my 6 BRA, and the latter two meter well for me. Some guys at Accurate Shooter have used H4350 in BRA and Dasher but you need a tall drop tube to stuff all that in to make it worthwhile.

Makes sense. I'll try 8208 first as I have loads and if that don't work then I'll get some Varget. Only thing I dont like about Varget is the poor metering / inconsistency.