I have had extremely good luck with asking for help from all of you so.... Here I go again. I am going to build a Varmint rifle on an AR platform. I have narrowed it down to these two rounds (.204 Ruger and 6 X 45). I am certainly willing to consider other ideas, but I am leaning towards these two... What round would you recommend and what twist rate would you suggest for the barrel. Of course if you have one or the other load data and results would be greatly appreciated.
Need advice on AR build .204 Ruger or 6 X 45????
- Thread starter Jm32526
- Start date
I'd hazard a guess that you will not be pleased with the performance of either past 300 yards.
I have been shooting Rockchucks, Coyotes, and the occasion Badger here in Idaho since 1978. The real fun is increasing the distance based on your growing skills and equipment.
That progression is based on larger capacity cases (flatter trajectories) and higher BC bullets.
I usually bring two or three rifles with me, and a friend to trade off spotting and shooting opportunities. My longer shots usually go to my 6.5 X 68S or 30-416 Sniper. My buddy usually gets to his 30-378 once we clear the AO to 500 yds.
I have been shooting Rockchucks, Coyotes, and the occasion Badger here in Idaho since 1978. The real fun is increasing the distance based on your growing skills and equipment.
That progression is based on larger capacity cases (flatter trajectories) and higher BC bullets.
I usually bring two or three rifles with me, and a friend to trade off spotting and shooting opportunities. My longer shots usually go to my 6.5 X 68S or 30-416 Sniper. My buddy usually gets to his 30-378 once we clear the AO to 500 yds.
RussellJ
Gold $$ Contributor
I use a 6x45 with a 20" barrel length. Sierra 80grn Varminter #1515 bullets with a full load of 8208XBR. Look at the knock down power of 1166 ft./lbs. of energy at 100yds. & 940 ft./lbs. of energy at 200yds with this load. That's 25% more energy than my 204R AR-15 with a 20" barrel shooting factory Hornady Superformance 40grn V-Max bullets. I'm getting 892 ft./lbs. of energy at 100yds. & 708 ft./lbs. of energy at 200yds. With the factory Hornady 32grn V-Max bullets in my 204R AR-15 the energy at 100yds. is 747 ft./lbs. and at 200yds. 552 ft./lbs. of energy.
The 204R will work however, the 6x45 will do it better.
If you want to wildcat, the 6TCU is what I am building my bolt gun on. 6x45 Ackley.
6x45, 1-8 twist, 85gr sierra, 24" barrel, I shoot 2" steel at 500 yds all day long
I am a big fan of bartlein barrels but they are currently not taking orders on AR barrels. I know the difference is minimal but would see an issue with a 1-9 twist? Have you had pretty good results? Is there a bullet you seem to lean more towards?
I couldn’t agree with you more. Shooting at longer distance is more fun. However I have a couple rifles built for that. I am looking for something to be effective 500 yards and in. I forgot to mention in my initial request.... This rifle will be for my wife. I was watching the outdoor channel the other day and they were doing a segment on shooting prairie dogs. My wife watched that and said that looked like fun. She then asked if I had something she could shoot and of course I said nope sure don’t i would have to build something that would fit. So I am looking for something with low recoil but will perform very well 400 yards and in.
I put a muzzle brake and suppressor on my 6x45. it is strictly a bench prairie dog rifle. the ar weights 13lb. 6mm bullits do a little better in wind
It depends on the varmint I guess. I shot many Prairie dogs past 400yds. and it does very vell.
my wife loves the 6x45 the only problem is I cant reload fast enough
Ive not shot a 204, but did build 2 20 Practicals for p-dogs & coyotes on a bolt & AR15 actions few years back. After dismal effects the wind (15-23MPH) had on the 20 calibers I got rid of them. I have shot tons of p-dogs with the 6x45 with 55g bullets in the range you want. One still needs to dial/hold for drift when the winds are blowing. The 6x45 is also very nice for deer sized game with a 80g bullet. I have 11 6x45s builds under my belt. I use 1/10" twist, heavy sporter bbls, 20" on AR15s and 22"-24" on bolt builds. I stopped using heavy varmint bbls since the heavy sporter is as accurate and carry weight is a bit less. If its going to be a bench type rig then yes Id go with a varmint bbl.
I stand corrected on the 6x45' performance capabilities.
jepp2
Gold $$ Contributor
Lots of different input so far, all hunt varmints much differently than I do. So without know if you are going to walk, or shoot from a table, how many rounds per year you expect to fire, distances you want to shoot at, etc. - you may get vastly different answers.
I shoot a lot of PD's each year (over 5,000 this year), so barrel life and recoil is important to me. I shoot by myself and have to spot my own rounds. So I shoot a 20P in a 10T 24" WOA varmint barrel. Always off a shooting table. I use an A2 stock with the butt stock weight in it. Balance is terrible, but it doesn't move when I fire it. I can spot hits with the scope on 24 power. When the pups come out in May, it is carnage. But you may hunt vast differently than I do.
I took 5spd’s recommendations back when I was on predator masters and looking at the 6 x 45. I now have several ARs and a bolt rifle in this caliber.
Unlike a .20 cal AR-15, a 6x45 can become somewhat constrained by standard 2.260" magazine length. Given that, stick with a 1:10 twist and run </= 75grain bullets, as going heavier (longer) results in too much case capacity occupied by a deeply seated bullet. I have a 6x45AI bolt gun on a 1:8, Simply because a bolt gun setup allows ~.250" more magazine capacity than an AR allows. That makes a huge difference in performance potential! The ability to seat a heavy bullet out long lets ya run a full case of powder behind it. That just can't happen in a magazine fed AR, as limited OAL stifles capacity when a long bullet has to get stuffed down the neck in order to clear/cycle in semi-auto 100%...
When shot side by side with a 6x45, the flatter trajectory of a .20cailber is quite evident. Of course, you're paying for that performance with decreased barrel life.
You can bang away with a 6x45, where a .20cal will heat up, fast. Both kill varmints well...
If you have any inkling of big game huntin with your AR, the 6x45 is a no brainer.
A 6x45 will be more efficient from a 'short' barrel...an 18-20" is dandy! Yet, going less than 22" on a .20cal is really cuttin' into performance potential.
If you do want a .20 caliber AR, just build a .20Practical. At the time I had mine built, Dakota was producing .20TAC brass, so that's what I went with. Today, I'd do a .20Prac & enjoy the brass bonanza.
The .204 Ruger is a fine cartridge, but it's extra case length doesn't make it ideal for cycling in an AR. That's not to say a .204R won't feed, just that a .20Prac retains parent case shape that that AR was designed to function on. And being that ARs like to beat up brass, you can run any matter of cheap, available brass and not give it a second thought...
Oh yeah, 1:10 for the .20 Practical, too! 32-40gr bullets with no worries...
Have fun!
When shot side by side with a 6x45, the flatter trajectory of a .20cailber is quite evident. Of course, you're paying for that performance with decreased barrel life.
You can bang away with a 6x45, where a .20cal will heat up, fast. Both kill varmints well...
If you have any inkling of big game huntin with your AR, the 6x45 is a no brainer.
A 6x45 will be more efficient from a 'short' barrel...an 18-20" is dandy! Yet, going less than 22" on a .20cal is really cuttin' into performance potential.
If you do want a .20 caliber AR, just build a .20Practical. At the time I had mine built, Dakota was producing .20TAC brass, so that's what I went with. Today, I'd do a .20Prac & enjoy the brass bonanza.
The .204 Ruger is a fine cartridge, but it's extra case length doesn't make it ideal for cycling in an AR. That's not to say a .204R won't feed, just that a .20Prac retains parent case shape that that AR was designed to function on. And being that ARs like to beat up brass, you can run any matter of cheap, available brass and not give it a second thought...
Oh yeah, 1:10 for the .20 Practical, too! 32-40gr bullets with no worries...
Have fun!
just build 2 uppers and shoot what you are in the mood for. that is what I did for a while
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