6mm Rem Loaded round neck diameter

[timoj731]

Hi all,

I am in the process of building a 6mm Rem Imp on a rem 600 action. I am wondering if anyone knows the loaded neck diameter of either Hornady or Rem standard 6mm Rem ammo? Just figuring out what diameter chamber reamer to go with.

Secondly will the 6mm Imp fit in AI AE .308 length magazines lengthwise (65gn vmax projectiles). I'm assuming it will fit ok but I havn't been able to find any internal length dimensions of the AE mags.

thanks, Tim

 

[gotcha]

Hi Tim, Just measured my 6AI fire formed Rem. brass, unturned neck, loaded round. They measure .270" to approx. .2705"..... My rifle is a single shot action so can't help w/ mag length. Curiously, the few factory 6mm Rems (75 grn bullet) I had squirreled away measured about .0005" larger on average. The factory ammo has a rather hard crimp to the cannelure & may have affected the measurement. Just thought it might be worth mentioning. Have you settled on a twst. rate yet?

 

[timoj731]

Gotcha,
Thanks for that. I've gone with a 27in 13.5twist kreiger, looking to shoot 55-75gners. Just building it as a flatshooting spotlighting rifle out to 300 yards or so. What weight projectiles are you using in yours?

 

[243winxb]

Don't you need a looooooong action for the 6mm rem. ?

 

[timoj731]

Should fit alright in the short action with the lighter projectiles. Heavier stuff i spose it could be an advantage to use the long action. Remington has done the 6mm on their short actions so far. I'm not loading above 75gn with this one.

 

[tjtjwdad]

Don't you need a looooooong action for the 6mm rem. ?

Mine is on a 40x action and I can shoot 105 AMAX & 107 SMK in single-shot mode w/o any issues.

HTH

 

[gotcha]

Hi Tim, Why not 900 yds + ? If you enter " Richard's" in the search feature at the top of this page. You'll pull up article by Richard Franklin which will answer many questions for you relating to twst rate & load developement w/6AI. I'm using a 12 twst, 26" Shilen & shooting the 80 grn Berger. Unfortunately, Berger no longer makes the 74 grn which was outstanding in my rifle. One of the things I learned to like about the 6AI is that looong neck. It really promotes ease of bullet seating & concentricity. Dale

 

[timoj731]

Thanks dale ,
Yep it's a good article, those two "guns of the week" on 6mmbr were what really got me interested in the cartridge to begin with. For daytime shooting Im looking forward to giving it a shot at those distances but as a spotlighting rifle the spotlight doesn't really go past 300ish! Ive got an l579 in 243 with a worn out barrel that I'm considering putting a 1in 10 or 12 on in the 6mm and using something similar to the bergers, I was thinking the 88gn bergers or even trying some of gs customs 69gn in it. Just gotta get the time to build these guns! How have you found the 6mm imp? I've heard some reports about it being a potentially finicky cartridge to load for, has this been your experience? Tim

 

[gotcha]

Hi Tim, 1st, not trying to sell you on 6mm AI. Plenty of fine varmint cartridges out there. 6 AI was my 1st "wildcat" & built to reach a little farther than .223 & 22-250 that I was using for PD control. Haven't found the 6AI to be as easy to load for as, say, 6mm BR. But not unduly troublesome either. RL-19 gave me best results accuracy & velocity wise w/ 80 to 87 grn bullets. Got that tip from John Siebel @ "varmints for fun". John is a decent, honest guy w/ much knowledge in the area of varmint cartridges. (waaay more than I) I'm sure John would be happy to lend his experience. That's what his site is all about. Not trying to blow you off. Drop me a PM any time, I'll be happy to help if I can. Dale

 

[timoj731]

Not to worry I've been set on the 6mm for some time! Thanks for this info ill check out his site and keep RL19 in mind, could be the go if I get around to building this second rifle. Tim