Leaning towards building a 6 x 45 on an AR 15 platform. Need help on twist rate: 1:9, 1:8, 1:10?? I also would like Recommendations on barrel length.

Let's please try and keep this to the topic at hand and not get an argument with everyone on here. And, don't insult anyone. I also don't want to hear or see anything written from two people who might be in a lover's quarrel...

depends on what bullet you want to shoot when i built one i used a 10" but i was only going ton use 70 gr and for them it worked well - i have shot a few 85 gr and it worked well

When I had the Savage 24 rebored 6x45mm, there was a choice of twist that ended up 9.5:1 for 85-grain bullets with a leade like a 243 (maybe 6 degrees?). So far, so good.

The 6mm-284 was a heavy barrel 243, not sure what twist is there but it will not stabilize 107-grain VLD so it's probably not a tight twist.

quote:

Originally posted by butchloc:
depends on what bullet you want to shoot when i built one i used a 10" but i was only going ton use 70 gr and for them it worked well - i have shot a few 85 gr and it worked well

I’d imagine that you could run into OAL issues with the heavy 6mm’s. That said, I really don’t think you could see any difference on paper, using an 8 or a 10 with 65-90 grain bullets. I’d just go 8, to cover all bases.

Unless you plan to shoot 105's or 108's. you don't need an 8 inch twist. 85's will stabilize just fine in a ten or even a twelve.
I built one in 1978 and shot 70's in it. It was a 14 twist. Regards, Bill.

I built my 6mm/223 on a Win. 70 that was originally a .222 Rem (that barrel was trash). I choose a Hart #3 contour with a 1-12 twist, and it shoots Sierra 80g Blitz and Horn. 75g V-Max very well. Twist depends upon what length bullets you plan on shooting. I figured 75-80g varmint bullets would be about right for the size of the cartridge case and for my intended use.

A side issue, I'm now changing over to copper for our lead-free rules, and the Savage seems to be stabilizing 80-grain copper TTSXs decently.

Same for 6mm-284, and I expected it would.

I shot a friend's AR 6x45 quite a bit and then had a 6x45 that was built on a Model 70 action for that I used as an NRA match rifle for 100, 200, and 300 yard reduced coarse matches. Mine had a 10-twist barrel and I used the 85-grain Sierra HPBT Game King bullets over a load of 24.5 grains of H322 in Winchester cases and Federal 205M primers. The gun and load would shoot 1/2-inch 10-shot groups at 100 yards and I ended up getting my NRA Highpower Master classification with the gun. I once tried 105-grain Bergers and the 10-twist barrel would not stabilize them. When I built my most recent match rifle, I thought long and hard about doing another 6x45, but ultimately went the 6.5 Grendel route because it is less effected by wind at 600 yards. I still play with the idea of building a light weight bolt gun in 6x45 because it was such an easy and pleasant round to reload for and shoot.

If you’re not planning to shoot heavier than 85 grain bullets, go with 10 twist. As other I’ve mentioned, might be running at a loss with the magazine for COAL if you go heavier than 85s.
As two barrel length, it’s really subjective to what your utility for the rifle is. If you’re looking for the best compromise of handling and portability versus velocity I’d recommend 20”.

My sako L-461 custom has a 1x10 18" barrel..It shoots sub 1/2 inch groups with about any load. I like the 75 and 85 gr. Monolithic bullets for deer and pronghorn and on a kudu cull some years ago..I like it for rock chucks in the windy Snake River Canyon of IDAHO..Its a grand caliber..

I really like the sound of the 6x45, but in the real world what was do better than a fast twist 223 shooting 65 to 75 gn bullets. Does the bigger calibre shoot them faster?

I have recently built a varmint barreled 223 and am loving using it on Roe deer and it shoots very well with 51gn Peregrine monolithic bullets.

Heym
Not much argument here, the 6x45 is just another but a very very nice option for the nuts who have everything

Ive had my 6x45 for 40 plus years, and my latest great caliber is the grand ole gal, the 220 swift, but there again its just another caliber..

What separates them is the rifle itself suchh as my 6x45 is a miniature African Dangerous game rifle in style with a blood red full fiddle back stock, 18" barrel, short forend, egg cheek piece, metal butt plate curved...Looks like a Holland that fell in the wash, thats what makes it a fantastic rifle!

quote:

Originally posted by Atkinson:
Heym
Not much argument here, the 6x45 is just another but a very very nice option for the nuts who have everything

Ive had my 6x45 for 40 plus years, and my latest great caliber is the grand ole gal, the 220 swift, but there again its just another caliber..

What separates them is the rifle itself suchh as my 6x45 is a miniature African Dangerous game rifle in style with a blood red full fiddle back stock, 18" barrel, short forend, egg cheek piece, metal butt plate curved...Looks like a Holland that fell in the wash, thats what makes it a fantastic rifle!

Sounds a lovely little rifle!!

quote:

Originally posted by Heym SR20:
I really like the sound of the 6x45, but in the real world what was do better than a fast twist 223 shooting 65 to 75 gn bullets. Does the bigger calibre shoot them faster?

I have recently built a varmint barreled 223 and am loving using it on Roe deer and it shoots very well with 51gn Peregrine monolithic bullets.

The 6x45 will have a 200fps+- advantage over the .223 due to the increased bore size being able to provide a more efficient combustion chamber for a more complete powder burn.
Also, there are some areas which have a 6mm minimum for big game.

It's a fantastic little round that just simply works, with nearly zero recoil and muzzle blast.

A couple years ago I posted a couple write ups on my loads and deer kills with the 6x45.
Several commenter's on here were not big fans.
I think mine was a 9 twist I'll have to look again but in my notes. The Sierra 85 grain HPBT was excellent on deer, longest shot 320 yards, 3 one shot kills, recovered one bullet.
The only issue I found with the 6x45 was at a glance they look just like a .223/5.56.
I switched to 25/45 just to avoid a problem.

I would go 1:9 twist with a 18" barrel and a mid gas length.

quote:

Originally posted by Snellstrom:
The only issue I found with the 6x45 was at a glance they look just like a .223/5.56.
I switched to 25/45 just to avoid a problem.

I color-code them, nickel plated cases for 6x45, brass for 223.

Just build a 6mm ARC

quote:

Originally posted by Austin Hunter:
Just build a 6mm ARC

another great little round but completely different feeding geometry and bolt face diameter.

http://forums.accuratereloadin...251050732#7251050732

Here was my 3 deer report from a few years ago.

Also some other facts:
Just thought I would post my recent results with this cartridge on Whitetailed Deer.
I recently put together an AR15 in 6x45, 20" McGowen barrel, 4-12 Leupold scope.
My bullet was 85 grain Sierra HPBT #1530, this bullet is a fairly hard bullet and NOT a Varmint bullet. With CFE223 powder I was able to attain over 2800 fps and groups right around an inch for 5 shots.
The first Deer was a Buck with an interesting 9 point rack, shot was broadside walking at exactly 150 yards, bullet passed completely through after breaking ribs in and out, destroyed the heart, exit wound was about the size of a Nickel, after the shot the Buck walked stiff legged and hunched about 30 feet and was done.
Second was a mature doe at 124 yards facing straight on, the shot entered at the ribcage/ neck junction breaking ribs and travelling into the body cavity and was not recovered. She dropped at the shot.
Third was a mature doe broadside at 312 yards, I wanted to catch a bullet so I put the bullet low through the shoulders. She dropped at the shot. Bullet passed through shoulder meat, rib, top of heart, rib, and shoulder meat and was caught by the hide on the far side, bullet weighed 36 grains which is 40% weight retained and was a perfect little mushroom.
Additionally my buddy graybird on this forum shot a coyote through the shoulders at about 200 yards and dropped it instantly with the rifle as well.
Overall I am impressed with the cartridge and how it really performs despite it's small size.
It is a pleasure to shoot and very economical using only 27 grains of powder and abundant 5.56 brass.
I will be building a bolt action rifle in 6x45 soon and send my AR15 barrel in 6x45 down the road for another project.

quote:
Originally posted by Duane Wiebe (CG&R):
Hmmm Snell: Near as I can figure, that tiny bullet dropped about 16" a 300 yds and had about 450 ft lbs energy left. About right?


Not quite Duane but close...
The specifics are 85 grain Sierra HPBT @ 2846 average fps, I figured about 9" roughly of holdover at the time because the rifle is sighted about 2.5" high at 100, dead on at about 215 yards.
At 315 yards according to the Sierra calculator the "tiny" bullet was still going about 2000 fps and 753 ft lbs of energy.
I routinely shoot my 300 yard gong with this rifle and a slew of other rifles, I'm lucky enough to have a range at my home so I get to shoot a lot year round.
If you like I can email you a picture of the "tiny" recovered bullet.....
I wasn't sure everyone wanted to know all the details but thanks for asking so I could share.

Counting kids, grandkids, and a few orphans, my 6x45 has killed at least 50 deer is my best guess..I personally have shot about a dozen or more deer and half that many pronghorn, been on a Kudu and springbok cull also..My bullet was the 80 or 85 gr. GS Custom and the 75 gr. Barnes that replaced the GS Customs out of necessity.