6mm rem AI for compitition?

[bozo699]

Hey Guy's,
I bought a reamer a few years ago for a 6mm AI for a long range varmint rifle build that I never built. I was wondering if in a 1:7.5 or 1:8 barrel using 105-115s if this could be a 600-1000 yard competitive rifle in BR ? I know 6*284 ( I have one) or other 6s are more popular but I have a nice new reamer, a new Lilja Barrel and was wondering if in fact could be competitive? Thanks Fellas for any any advise in advance.
Wayne.

 

[Baron]

Wayne,
Yes it will work quite well with the right brass. I would lean toward the 1 in 8", with 105 - 108 class bullets.
Baron

 

[bozo699]

Baron,
Thanks for the response, Brass was a concern of mine, would you use winchester or would you rework 7x57 Norma brass?
Wayne.

 

[tiny68]

I had Dave Tooley build me a M700 with a Harted barreled 6 Ackley with a 1:9 twist. That was his recommendations for the 107s. He was right. It is a hammer. Under max loads, RP brass doesn't hold up well. 4-5 firings and the primer pockets are lose. My experience is the 107s don't shoot as good over 3100 fps. However, you can hammer the 95 Berger VLDs up to 3,500 fps. I am just finishing up making up 100 RWS brass for 7x57 parent brass. This RWS brass is hard stuff and it should last a while. Time with tell. This is what I will shoot in FClass this year. David Tooley said runner till she burns out then we will she it back and go again...

Luck, Tim

 

[Steve Blair]

I have a straight 6mm Remington built on a 700 long action and reworked and barreled by Stan Ware. I has a 30" 7.5 twist Bartlein MTU contour and shoots Berger 115 VLD molys loaded to 3170 into small clusters. I have not yet shot it in competition, too busy with F-TR. As soon as the winter High Power matches are over, I will try it in Varmint Silhouette matches at Pala. I cannot use a bullet over 108 at that match and developed a load using Sierra 107 molys. My experience is similar to Tim's; The Sierra 107 shoots best well under top velocity. My best is a mild load of H4350 at 3150.

 

[40X Guy]

The 6AI is a definite hammer for just about any form of shooting. I have 2, and the one I use for the local LR groundhog shoots is based on a Rem 700 BDL action with Broughton HV profile 8 twist finished at 28.5 inches with Vais brake. Finished 2nd in last GH shoot of the year in very windy conditions at a 2-500 meter shoot. Had best group at 500 meters. The 6 Br's were not bucking the wind that day. My load is light as it seems to like the 3150-3200 fps node. I tried Berger 105's, Sierra 107's, and Lapua 105's and all were outstanding while working up loads at 1 and 200 yards. But ended up going with the Lapua 105's as the ES and SD numbers were excellent. Load is mild with 48.0 grains of H4831SC with Fed. 210 GMM primers and .005 into lands. I did go thru the trouble of working over/necking down the Norma 7X57 brass after reading about the process on this site as my neck on this rifle is SAAMI spec .278, so with the Norma brass my loaded neck diameter is right at .275. Next for this rifle is a Lone Wolf 1000BR stock and I am going to let it stretch its legs this next shooting season.

My second 6AI (new acquisition) is a 40X single shot action with a Shilen select match 8 twist .269 neck that I am going to do work ups with the 95 grain bullet class. IMHO I don't think you can go wrong with a 6AI for any shooting discipline. Something to be said for the longer neck on the case as well. Keep us posted!

Frank

 

[1000yardstare]

Used a 6AI in F Class at the 2009 Ontario Championships. Was in a 3-way shootoff for the 1000 yard title. Lost by one point. Don`t even get a handshake for 2nd place.

Beauty cartridge. Had a 30 inch MacLennon 8 twist barrel on a blue printed Rem 722 action, Fajen prone stock, Timney trigger, Anschutz fittings, Harris bipod. I have never used a front pedestal.

Load was SMK 107, Win brass and primers, 49.0 gr RL22, COAL 3.055. Chronod at 3250 fps. Only needed 20 minutes of up at 1000 yds from a 300 yd zero. Wind correction was 6 minutes at 1000 yds in a 10 mph crosswind.

Used a 6-24 Bushnell 4200 Tactical with 30 mm tube. 6AI shoots so flat that didn`t need a long range scope base.

But there are tradeoffs in every story. I enjoyed shooting the rifle so much that the barrel was toast after one season. Groups under 1/2 moa up to 1200 rounds, under one moa up to 1500 rounds. After 1500 rounds the bullets seemed to be going where they wanted to on the target at 1000 yds. After 1800 rounds couldn`t keep the shots on a pie plate at 300 yds.

So depends on your philosophy. Is the barrel just another expendable component like primers and powder? Or do you worry about barrel life and take `er easy?

 

[bozo699]

WOW fellas I am excited with all your stories , Thanks.
I was worried that you would all tell me to shoot a 6*284 or 6br or something that is known to work, I already have those and wanted something a little different, my smith has had this reamer of mine for years and I thought I might as well use it. I have a 6AI with a 1:14 that I use on GHs out to 400 or so with excellent results but never in match shooting. I now have some high hopes on long range Br on windy days with it.Yes Frank I absolutely believe the barrel is a expendable component and NEVER worry about barrel life, accuracy I do. I am like you I shoot for fun and hopefully to win when the barrel no longer has it in it to do that I will gleefully screw another one on it Now for the Brass dilemma, I think I will put a add on here for some RWS if I get no replies I think I will try Norma. I think I will call my smith and get the ball rolling, he is right in the middle of building my son and I a couple of 6brx's but I will tell him so he can be thinking about it. Thanks again guy's for your thoughts Ideas, and experiences with the 6AI.
Wayne.

 

[40X Guy]

I am like you and don't worry about barrel life either. This new AI that I acquired is going to be leaned on. ;D. Curious what your reamer specs are? And don't be afraid of Win. brass, thats what i am going to use in my new AI, but will have to be neck turned to fit chamber. The only reason I necked down Norma brass was to help fill the void in my .278 chamber. Worked perfectly, and brass is holding up well. Very concentric solid brass.

Frank

 

[bozo699]

Frank,
I guess it was 1000yardstare that said that about expendable barrels,sorry about that. You are the second to ask about the reamer specs. I don't have it here, haven't seen it in years and don't even remember what we had in mind at the time other than we bought two reamers, one for short ranges in mind and the other with longer ranges in mind. I already built one for short range. The smith that originally got them for me is no longer in business but I am sure we have paper work in the box with it.
Wayne.

 

[Kenny474]

Wayne, before you go and dump money into Norma brass that needs to be formed, give the Winchester a shot. It's not quite Lapua, but it's usually very nice brass. I have 100 for my 22-6mmAI that have been sorted by weight, and they are quite consistent with uniform necks as well. I used Winchester brass in my 6-284 and never had issues, even when running it hard.

With the low cost of the Win brass, it's definitely worth a shot. I think I paid $44 per 100, which is short money in my book. If I get even 6 loadings from it, that's $88 in brass for the life of the barrel, not bad in my book. Especially when it's as consistent as it is.

Kenny

 

[bozo699]

Kenny,
I actually have quite a bit of the win on hand as that is what I have been running in my other 6AI. Thanks for the insite I will give it a try. My other 6Ai shoots 65 gr v-maxs bullets in the mid 2s with the 39 gr IMR 3031 and win brass, and 210m primers I stopped when I got there as I didn't need to wear the barrel out looking for anything better. Its a groung hog killing machine out to 400yds or so, it will go further but the wind starts playing havoc on the little 65s much past that.I did kill a coyote @ 623 yards with it once Lucky??
Wayne.

 

[Steve Blair]

I have always used Winchester brass in 6mm. The downside is more preparation, the upside is price. 10-14 reloads is typical for full pressure loads. There was a brief flirtation with Remington brass when Winchester was unavailable but it could not take the pressure very long.

The latest rifle has a Lone Wolf Mk 1000 and chamber with .271 neck. It was Stan's reamer and I don't know the throat dimension but OAL with Berger 115 VLD just touching is 3.050. That leaves about .19 below the N-S junction. It could be just a little longer, say around 3.15 OAL. That would still leave .139" engagement for the Sierra 107 and .198" for the Berger 115. If I keep shooting stiff loads, it will be there soon.

 

[1000yardstare]

Didn`t mention the reamer in my first response. My `smith owns it, a no-turn neck for Win brass. He said Norma 7x57 is too expensive and Rem 6mm brass is too soft so I have always used Win brass with good results. Have 7 reloads on some of the cases and they are still in good shape. Used a .269 bushing in a Redding neck die. Bumped the shoulder .001 with a Redding body die. Didn`t want chambering problems during an F Class match on a hot Summer day.

Most of his customers for the 6AI are coyote hunters and want the screaming velocity of the lighter bullets so the reamer was throated for the lighter bullets. When I asked him to lengthen the throat for the 107 SMK he said "Why don`t you poke me in the eye with a stick?" It is a pain in the butt to get the long axis of a throating reamer coincident with the long axis of an existing chamber. So it cost me extra but it was worth it. He slightly short-chambered the barrel to ensure a crush fit while fireforming.

Bye the bye, that 6AI brass is now necked up to 6.5 mm in prep for the Shilen 8 twist Special Match barrel being chambered with a PT&G 6.5x57AI reamer even as we speak. Will be using 142 SMK and 139 Scenars and probably RL22. Same action, scope and fittings. I sent some fired cases to PT&G so they could compensate for the slight short chambering.

 

[GWY]

I've been following this thread with great interest and am thinking of rebarreling to 6mm Rem AI with a 7.5 twist barrel to shooting 115 DTACs for 1000 yard competition.

What is the standard method of fireforming brass? Is it simply firing a standard 6mm Remington reload in the chamber, or does the bullet have to be seated out long (jammed) for proper "headspace" during this process?

Thanks in advance.

GWY

 

[bozo699]

GWY,
Welcome to the forum
A lot of guy's like to use the false shoulder method when fire forming brass, I myself have not used it and don't care to as you have to work your brass more and I have had good luck just seating my bullets into the lands. I have also shot factory rounds in mine with no real problems but did notice the primers had backed out a little but fire formed to the chamber ok.
Wayne.

 

[1000yardstare]

GWY...........the proper method for fire forming an Ack Imp is to slightly short chamber with the reamer to create a crush fit.

The only support for a standard 6mm REM case in an AI chamber is the junction of the neck and shoulder. Short chambering by a few thou ensures that the brass at this junction is jammed into the same area in the chamber.

Running an AI reamer into the same headspace depth as a standard 6mm Rem case will create excess headspace in the fireforming process and you will see the primer backed out a few thou.

The crush fit method is very positive and you don`t have to fool around with false shoulders or jammed bullets.

 

[Kenny474]

GWY,

Again, welcome to the forum.
When fireforming AI brass in a properly cut AI chamber, which is a bit different process than some of the other improved rounds such as the Dasher, you simply need to load a "normal" load and fire as usual. The neck/shoulder junction is actually supposed to be a few thou short of the standard chamber so you get a crush-fit with standard brass. That way, no jamming or false shoulder BS is necessary.

Kenny


EDIT: sorry, 1000yardstare posted while I was typing and doing stuff, so he beat me to it. ;D

 

[CanusLatransSnpr]

Guys, thanks for this thread! I just stumbled onto it and have been kicking around the idea of a 6mm A.I. build myself. I'm thinking a 28" 10 twist barrel throated to shoot the 87gr. Vmax bullets for a long range critter getter ! If I could push these bullets 3,600 fps I would be more than happy! My question is, how do I go about figuring out how long the throat should be on the reamer that I order? If someone could give me the base to ogive length of an 87gr. Vmax bullet I could do the math to obtain how long the throat needs to be I think? On the other hand, with the difficulty in obtaining those Vmax bullets, I may have it throated to shoot something that is a little more readily available! Thanks!

Mike

 

[bozo699]

GWY,
Well there you go, I have learned something new as well. That explains why on some loads my primers have backed out, my reamer must not have been cut right to give a crush fit. Thanks 1000yardstare and Kenny.
Wayne.