Custom Rifle Build... 6mm Remington Ackley

[Bwhittty]

I have a question fellas. Have stock ready to go in safe. Remington Short Action and Brass headed this way. My worry is the short action. I do NOT want to single feed or have to pull the bolt to eject shells. I'm ordering a 13 twist barrel because I want to shoot the 75 Vmax's only. Am I going to have an issue with this short action and these bullets???

 

[shortgrass]

Yes, even with a Wyatts mag box added, the mag will be too short. The 87g have been the longest for SA, even with a Wyatts box. You'll screwing up with a 13 twist bbl., too. You'll need a 1-8 for best rsults. 13 twist just isn't enough. LA,,,, 1-8 twist.

 

[AZShooter]

The twist is right on the edge. It might not work for some of the longer 75 gr bullets. I would crunch this ballistics calculator adding the bullet's length to the input to be certain.
http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi


As for fitting the magazine, seat the bullet to fit the existing mag box and see how it feeds. It might work out just fine. If not then you can add the Wyatts mag box:

CFE-5 Magazine Box, WYATT'S OUTDOOR, INC.

I added a wyatts mag box to a SA Rem and it allowed me to fit and feed a 6mm-284 with bullets up to 105 grs just fine. The 284 brass is slightly shorter than the 6mm Rem 2.170" vs 2.223". The 6mm Rem case is only .053" longer.

The Wyatt's mag box inside dimension is 2.995" The Sammi OAL for the 6mm Rem is 2.825" so you will have some leeway for seating that short bullet.

You could supply a dummy round when ordering a reamer to get the fit to lands you desire as well as neck clearance and other things.

 

[shortgrass]

6mm Rem Ackley Improved 40* shoulder loaded with 107g SMK that sits .015" off the lands in my chamber. Sitting in a Wyatts MBE-5 which has the same inside length as their CFE-5. Hart 1 in 7 twist ('cause I shoot 115g DTAC, also). Barrel has been Melonite/Black Nitride treated when 'new'. Not the first 6mm AI I've built!

 

[Bwhittty]

Yes, even with a Wyatts mag box added, the mag will be too short. The 87g have been the longest for SA, even with a Wyatts box. You'll screwing up with a 13 twist bbl., too. You'll need a 1-8 for best rsults. 13 twist just isn't enough. LA,,,, 1-8 twist.

Appreciate the advice and opinions. I'm not running heavy bullets though. I have a 6.5-284 that I will use if the wind gets to Rollin or the shot is past 8 Bills. I will only be running the 75's. This is strictly a varmint gun with the mist factor definitely in effect in this build. I'm a little confused with your first sentence. So ur saying 75's and 87's shouldn't be a problem with the extended box added???

Thanks
Brett

 

[sable tireur]

Bwhittty,

Apparently there is a little confusion somewhere...

According to my math, your 75 gr. AMAX, when seated to an OAL of 2.825" is a pinch over 0.200" in the neck of the 6mm AI case. The modest velocity achieved in a 26" barrel should be approximately 3600 fps+. So, a little more math and I come up with a 1:13.4" twist rate for your combination.

Now unless I missed something somewhere, you should be good to go.

Regards.

 

[shortgrass]

Appreciate the advice and opinions. I'm not running heavy bullets though. I have a 6.5-284 that I will use if the wind gets to Rollin or the shot is past 8 Bills. I will only be running the 75's. This is strictly a varmint gun with the mist factor definitely in effect in this build. I'm a little confused with your first sentence. So ur saying 75's and 87's shouldn't be a problem with the extended box added???

Thanks
Brett

Sorry, had .224s on my mind for some reason. Should be OK with your 75g. I would go with no less than 12 twist though. I'd rather have a bit more than needed than not enough. Mine is a "varmit rifle", too. I just reach out further. The wind blows all the time here, on the Southern Plains. The 6.5mm x 284,,,,, shootin' 142g there. No sense in my mind to have a "big ol' case" and a tiny bullet. I shoot the 75 V Max in a 6mm x 45 and sometimes the 80g Blitz. I get the 'mist' on praire dogs with the 6mm Ackley and 107/115s, too.

 

[Bwhittty]

Bwhittty,

Apparently there is a little confusion somewhere...

According to my math, your 75 gr. AMAX, when seated to an OAL of 2.825" is a pinch over 0.200" in the neck of the 6mm AI case. The modest velocity achieved in a 26" barrel should be approximately 3600 fps+. So, a little more math and I come up with a 1:13.4" twist rate for your combination.

Now unless I missed something somewhere, you should be good to go.

Regards.

Thanks buddy. Appreciate you doing that for me. I am actually going to use the VMAX, not the AMax. Does this change my twist at all??

 

[Bwhittty]

Sorry, had .224s on my mind for some reason. Should be OK with your 75g. I would go with no less than 12 twist though. I'd rather have a bit more than needed than not enough. Mine is a "varmit rifle", too. I just reach out further. The wind blows all the time here, on the Southern Plains. The 6.5mm x 284,,,,, shootin' 142g there. No sense in my mind to have a "big ol' case" and a tiny bullet. I shoot the 75 V Max in a 6mm x 45 and sometimes the 80g Blitz. I get the 'mist' on praire dogs with the 6mm Ackley and 107/115s, too.

No worries buddy. Thank you for ur replies and knowledge on the subject.

 

[sable tireur]

Bwhittty,

I am actually going to use the VMAX, not the AMax. Does this change my twist at all??

Apparently some of us are having keyboard/brain dysfunctions today...

The numbers I worked out are for the VMAX bullet but I typed 'AMAX' instead. DUH!

Regards.

 

[HARPERC]

Thanks buddy. Appreciate you doing that for me. I am actually going to use the VMAX, not the AMax. Does this change my twist at all??

I don't see the advantage of a 13" twist, over a tighter twist. My 1-10" 6mm shoots the 75 grain bullets very well.

 

[sable tireur]

HARPERC,

In terms of accuracy, there is a rule which states that the slowest twist rate which will stabilize a particular bullet given a specific velocity will be the most accurate.

Now, everyone can fuss about the terms accurate and accuracy because they can mean different things to different people under different conditions, of course. Here we are discussing the utmost accuracy with a particular bullet which is the 1:13" twist rate.

Talk to the guys who shoot the 30 BR cartridge in Point Blank competitions. They use slow twist rates from 1:14" to 1:17" based on shooting very light weight .30 caliber bullets made specifically for best accuracy.

Regards.

 

[HARPERC]

HARPERC,

In terms of accuracy, there is a rule which states that the slowest twist rate which will stabilize a particular bullet given a specific velocity will be the most accurate.

Now, everyone can fuss about the terms accurate and accuracy because they can mean different things to different people under different conditions, of course. Here we are discussing the utmost accuracy with a particular bullet which is the 1:13" twist rate.

Talk to the guys who shoot the 30 BR cartridge in Point Blank competitions. They use slow twist rates from 1:14" to 1:17" based on shooting very light weight .30 caliber bullets made specifically for best accuracy.

Regards.

Good post, especially regarding accuracy meaning something different in each context goal or rules.

My answer was based in my perception of the 6mm Remington being better used as a varmint/game cartridge. Being typically a hunting site we often incorrectly "assume" questions are asked in that context.

Granted some good BR work has been done with the 6mm Remington, but given the situation with brass, and the success some of the other choices are having it would be difficult for me to consider it in a BR rifle. As much as I've enjoyed mine, the logistics are such its difficult to recommend it as a good choice in the varmint/game class as well, in spite of it's many positive characteristics.

Ironically, my 6mm with the 1-10" consistently has provide better groups as bullet weight declines. To the point I've wondered at times if Shilen marked it wrong. Again not a disadvantage for it's purpose, a 7.5 lb, scoped, first rifle for kids, and ladies, with an occasional coyote for me.

I have a .223, 1-8" that behaves more typically as you describe, with the 75's more consistently scaring the 0.25" mark, and progressively declining as bullet weight drops, and it's more likely to be closer to 0.75". The smallest target being sage rats, and the 53 grain V-Max usually provides the kids minute of rat to about 200 yards.
Thanks,
Carl

 

[Bwhittty]

HARPERC,

In terms of accuracy, there is a rule which states that the slowest twist rate which will stabilize a particular bullet given a specific velocity will be the most accurate.

Now, everyone can fuss about the terms accurate and accuracy because they can mean different things to different people under different conditions, of course. Here we are discussing the utmost accuracy with a particular bullet which is the 1:13" twist rate.

Talk to the guys who shoot the 30 BR cartridge in Point Blank competitions. They use slow twist rates from 1:14" to 1:17" based on shooting very light weight .30 caliber bullets made specifically for best accuracy.

Regards.

I was working off of this article for my specs....

6mm Remington Ackley Varminter