6mm Build I have been kicking around

[jacq220]

Not really any questions, just figured I would enjoy a little discussion and see what yall thought about this build concept since I am getting close to pulling the trigger.

6mm Remington AI
Fluted 8 twist finished at around 27 inches long, threaded w/ protector med varmint contour
Remmy receiver, long action
fluted bolt badger knob
Jewel trigger
PTG bottom metal alpha mags
McMillan HTG adjustable in gap camo
vortex pst 6-24x50 FFP moa/moa

the goal will be 105 Amax's or berger hybrids at hopefully above 3200 fps

 

[Austan]

A couple quick questions since I'm in a similar thinking mood right now concerning a 6mm rem AI or 6-284, why the barrel so long (IMO 24") and why the long action instead of modifying a short to handle a longer OAL (milled feed ramp) and use type 2 mags? Otherwise, dandy selections everywhere else.

 

[jacq220]

Good questions.... Long action because I am planning on PUSHING these bullets, so I don't know what barrel life it is. I can do almost any caliber I want with a rebarrel, not true for the short action. And I plan on loading them long and don't have the action already so its cheaper to just get the L/A. And I was really torn between 6mm ai and 6mm swede so if I want some more ass out of this round I can even rebbarrel to a 6mm 06

the flutes on the barrel are designed for a finish 26 inch's, so I can always cut it back to there, but I figure a couple of extra inch's will be nice since I don't spend a TON of time carrying the rifle, and if I somehow was forced to, I could suck it up and drive on for a few days hunting anyways.

 

[Austan]

Gotcha, looks like you got it figured out. Should be a fun rifle, now you just have to find components.lol

 

[JGorski]

Do either of you guys know how much H2O the 6mmREM AI holds? Just wondering how much RE17 it'll take to make it shoot. 41grs with 6MMREM is pretty accurate with 105HYB.

 

[mkollman74]

Just my experience, but I had nothing but trouble from the 5 Alpha mags I owned.

 

[jacq220]

I love my alpha mags on my short action. Had to tweek the feed lips just a bit but they have been perfect since then. and they are much shorter than that AI 10 rounders.

 

[T J]

A couple quick questions since I'm in a similar thinking mood right now concerning a 6mm rem AI or 6-284, why the barrel so long (IMO 24") and why the long action instead of modifying a short to handle a longer OAL (milled feed ramp) and use type 2 mags? Otherwise, dandy selections everywhere else.

Like most high powder capacity/small bore cartridges "overbore" (& also my favorite) the user/shooter is trying to get the highest amount of velocity possible from a given bore size. I have both of the above cartridges, the 6mmAI in a Savage 110 & teh 6-284 in a 700 LA. I promise you, you will hate life trying to push either through a short action or a short barrel with heavy bullets.

I'm speaking of course, about pushing a heavy bullet as fast as possible. The easiest way to accomplish this (I don't like the word "best") is a heavy dose of slow burning powder & slow burning powder takes more time to burn, thus the long barrel. The 6mmAI could probably be ok with no less than 24" although I would not condone that. The 6-284 is a waste of time in a short barrel. Think about the .264 win when it first hit the scene. The advertisement was something along the lines of: "It makes a helluva bang & packs a helluva wallop!". The 24" barrel was the root cause of the "helluva bang" effectively handicapping the effectiveness (read velocity) of what I consider an outstanding hunting caliber. The second advantage of a longer barrel is, at some point you WILL have to set it back & that time is usually a lOT sooner than you want

Now onto barrel life. The AI due to case design & capacity will out last the x284. The x284, due to powder capacity (all other factors being equal) will outrun the AI. The rest of the story is up to how hot you get the bore while still shooting.

Both are outstanding calibers that are atop the 6mm crowd when performance is considered. Both cartridges are capable of 1/2 moa accuracy with the x284 gettin the nod in the brass life department (lapua vs Rem).

Just my .002 gents, keep in mind that I am not a tactical shooter, I either shoot prone LR/ELR or I'm hunting thus the basis for my input.


t

 

[Jedi]

Building on a long action makes way more sense than using a short action
I have built my last S/A rig

research 6mm crusader, GAPS take on 6mm AI
IIRC coppercreek has brass on hand so no fire forming

Melonite barrel will help round count

Wetcap
6AI = 60
6/284 = 66

FYI
6xc RE17 107smk =3300fps

31" barrel

 

[sandwarrior]

Short action only makes sense if you load 85-90 gr. bullets. Long action is my suggestion. I own and shoot a .243(several), 6mm Rem, 6mmAI, and 6-284. Of all of them, I like the 6mm Rem the most. It's right on the edge of overbore. It will smoke barrels just like any of the above mentioned if you don't slow down with the load and the shooting. With a long barrel (27") I was just able to get 3200 fps with a 105. I've had better velocity from the AI and the 6-.284 but both have had the barrels set back more than once.

If I were going to go for an 'improved' cartridge with the goal of velocity, I would work on the 6x55 imp. (6.5x55 Swede necked to 6mm and then improved). This will keep the overbore situation (too much case in comparison to bore size) about right on the edge. I wouldn't neck it to 40 deg. though. I'd either leave it at 26 deg. or blow it forward to 30-32. This optimizes the flow/pressure situation. The long neck will also help save your throat. One step down from that would be the .243 Imp. You can go with an AI, but I still feel that the 40 deg. shoulder is too steep for that bore diameter. I would bump it to 30-32 to optimize flow/pressure ratio. Lapua makes excellent brass for both the parent cases.

A .243 and 6mm Rem won't burn barrels if you don't burn barrels. Go out and hit a prairie dog town with 250 shots in one day and you WILL go through a barrel. You simply HAVE to back off the shooting in anything bigger than a 6mm BR if you don't want to burn barrels. The new competition cases like the 6mmXC, 6x47 (Swiss case), 6mm CM and 6mm SLR are still going through a lot of barrels when used in heavy competition. Just not as fast as their predecessors.

That said, straightening out the case walls, as you probably know, help the cartridge grip the chamber better. The tapered cases like the Savage .250 and Mauser cases (6mm Rem) can't run as high of pressure because of that. You'll get too much bolt thrust (case pushing back against the bolt face). Again though, the way to beat that is slower powder which causes longer, lower pressure pushes on the bullet.

 

[jacq220]

I agree with all of the above. I plan on pushing these bullets and the longer neck over the .243 and other similar class cartridges from what I understand will really help with barrel life. 2,000 rounds is my goal and I doubt I will struggle to attain that. I don't think you could burn a barrel up with 250 rounds in one day with this cartridge.... I liked the 6x55 but didn't want to mess w/ an extra step. with the 6mm Remington ai I can fireform my loads and do load development, or just buy some 6mm Remington and shoot, when I am done I will have brass and accuracy should not suffer one iota.

anywho, the sock has been ordered and downpayment made. the barrel is also in stock at bugholes, so the only thing the smith will have to wait on is the reamer which shouldnt be terribly long.

 

[rrflyer]

A 243 will do what you want easily. George's 243, last I read, had 2500+ rounds down it.

 

[jacq220]

I don't want a .243 just seems to plain. 6mm Remington AI is what I am going with. I have wanted to try one for a long time.

 

[rrflyer]

I don't want a .243 just seems to plain. 6mm Remington AI is what I am going with. I have wanted to try one for a long time.

Good enough reason for me

I think a 6mm-300winmag would be badass. See if you can get the 105s up to 3700+

Barrel life would probably suffer

 

[T J]

I don't want a .243 just seems to plain. 6mm Remington AI is what I am going with. I have wanted to try one for a long time.

You won't be disappointed with the 6mmAI, good choice. Rock it in a Long Action & kick some 6.5 ass


t

 

[AMG04]

To add to the general discussion...

I had a Mauser action laying around so I decided to run 6mmAI with a 27" 12-twist barrel. 'Smith is currently putting everything together for me. I plan to hunt varmint with it mostly so I requested a slightly shorter throat to shoot the 75gr V-Max. I am hoping to get about 3500fps with modest pressure from VV-N550 or N160. It looks like I can push the 75's up to about 3800fps with RE-17 or H4350. Not sure that its necessary though. I dont intend to punish the brass to much...

When it comes time to re-barrel I would like to switch to an 8-twist and run the 105 A-Max or 107 SMK. That should be a great LR round.

Once you pull the trigger on the build and get it out to the range be sure to share the results. I would like to know real world ballistics on the 105's, drop & windage...


-Cheers

 

[T J]

To add to the general discussion...

I had a Mauser action laying around so I decided to run 6mmAI with a 27" 12-twist barrel. 'Smith is currently putting everything together for me. I plan to hunt varmint with it mostly so I requested a slightly shorter throat to shoot the 75gr V-Max. I am hoping to get about 3500fps with modest pressure from VV-N550 or N160. It looks like I can push the 75's up to about 3800fps with RE-17 or H4350. Not sure that its necessary though. I dont intend to punish the brass to much...

When it comes time to re-barrel I would like to switch to an 8-twist and run the 105 A-Max or 107 SMK. That should be a great LR round.

Once you pull the trigger on the build and get it out to the range be sure to share the results. I would like to know real world ballistics on the 105's, drop & windage...


-Cheers

I put a 12" twist on my 6mmAI & 8" twist on my 6-284. Running an 85grainer @ ~3500 out of the 6mmAI with good brass life & running the 107 out of the x284 @ 3440, It's Lapua brass I'm not worried.


t

 

[AMG04]

That is one downside to the 6mmAI. It looks like R-P and W-W are the only manufactures making 6mm, unless you want to neck down 7x57.

TJ, have you tried both R-P & W-W for the 6mmAI? If so, which did you like better? Quality, Consistency, Prep Required...Etc.

 

[T J]

Wish I could help more, I've only used R-P. There will be more work at the loading bench to get the consistency you need for long range shooting but oh well.
For most shooting <500 I wouldn't worry too much about sorting etc. I just do the normal: Form, Size, Trim, Chamfer, Deburr & uniform. It's been working pretty well so far.


t

 

[jacq220]

Not worried about brass availability, if it shoots sub moa out to 850 or so that's all that matters to me. a 12 inch group at 1k will be an accomplishment for me w/ the type of winds I shoot in here. I really doubt I am a good enough shooter to notice a difference between GREAT handloads in cheap brass vs. GREAT handloads in lapua brass.

 

[jwp6114]

Fyi

If u are shooting in gusty winds I would go with a 7mm or 30 cal, wind isn't usually bad here... I shoot a 243AI 28" 8 twist kreiger.

I have had the 105 hybrids up to 3460 with 49.0gn of 4831sc but the bullets didn't like it...

Shoots 1.5" or better at 600 yds

 

[jacq220]

I can hold my own in the wind. this 6mm will still have significantly less than the .308 I am selling to help fund it, and that's all that matters.

 

[JGorski]

I don't want a .243 just seems to plain. 6mm Remington AI is what I am going with. I have wanted to try one for a long time.

Thats why I didnt get the 243, thought the 6mmREM was better, longer neck, bit more speed, just more interesting round. But now Im having it rebarreled in 6Creed.

 

[JGorski]

Fyi

If u are shooting in gusty winds I would go with a 7mm or 30 cal, wind isn't usually bad here... I shoot a 243AI 28" 8 twist kreiger.

I have had the 105 hybrids up to 3460 with 49.0gn of 4831sc but the bullets didn't like it...

Shoots 1.5" or better at 600 yds

Thats my goal Im shooting for in my 6Creed, Id love to see some pics of your rifle and the specs if you dont mind.

 

[mkollman74]

I love my alpha mags on my short action. Had to tweek the feed lips just a bit but they have been perfect since then. and they are much shorter than that AI 10 rounders.

They are shorter, but mine did not function as 10 rounders. Once I put the 8th round in them, they would bulge so badly that they would not seat consistently, and were an absolute pain to work with. Feeding was also suspect. I thought perhaps I had other contributing issues with the feeding, but a switch to AI mags made everything better. I am glad yours work for you, but I'll never purchase another one.

 

[jwp6114]

Thats my goal Im shooting for in my 6Creed, Id love to see some pics of your rifle and the specs if you dont mind.

Range day Sunday, will take some and post up for Monday...

 

[jwp6114]

If your shooting for 1/3 or sub groups, prepair to wast countless hours behind the reloading bench, it once took me 8 hours to make 100 cartridges...