Clone correct mk12 mod 1 collar

krinkydink

Private
Minuteman
May 4, 2019
1
0
2
I recently became aware that there are 2 Allen engineering MK12 collar lengths, a long, and a short (to resolve the issue of running into the gas block/fsb on some guns). To the best of my knowledge both lengths would work with a MK12 mod1, but I don't know if one is "clone correct" for a mod 1 and the other is not. ADCO list the long as for Mod 0s and shorts for Mod1s, but I know the shorts were used on later Mod 0s so im taking that with a grain of salt. I know its a pretty nit picky thing, but if I'm going though the trouble of hunting down a Colt BCG and keyhole upper I might as well make it 100% clone correct.
 

TexasBJ40

Private
Minuteman
Aug 30, 2018
3
1
6
I wasn't aware ADCO sold the collars separately. Looks like I'll be purchasing one from them as well.
 

mheimer_45

Full Member
Belligerents
May 19, 2013
260
49
34
NW Kansas
I could be wrong but it appears on AE website the collar lengths are for different suppressors. It seems the short collar is for an SPR barrel with an AEM5. The long collar is for the AEM2,3, and 4.
 

TexasBJ40

Private
Minuteman
Aug 30, 2018
3
1
6
I could be wrong but it appears on AE website the collar lengths are for different suppressors. It seems the short collar is for an SPR barrel with an AEM5. The long collar is for the AEM2,3, and 4.

If you look at this picture, you can see the differences in collar length for the AEM5. Besides the extra length, it works the same as the short collar. You can see there is not a space between the collar and FSB on the picture of the early MOD 0. You may be thinking about the SPR to M4 Adapter which would mount the same way and looks very similar, but is for use with the suppressors you mentioned.

71187997118805
 
  • Like
Reactions: FatBoy

mheimer_45

Full Member
Belligerents
May 19, 2013
260
49
34
NW Kansas
I learn something new everyday here. Thanks for that info.

If you look at this picture, you can see the differences in collar length for the AEM5. Besides the extra length, it works the same as the short collar. You can see there is not a space between the collar and FSB on the picture of the early MOD 0. You may be thinking about the SPR to M4 Adapter which would mount the same way and looks very similar, but is for use with the suppressors you mentioned.

View attachment 7118799View attachment 7118805
 
  • Like
Reactions: TexasBJ40

TheGerman

Oberleutnant
Belligerents
Jan 25, 2010
5,335
5,647
219
Out West
I think PRI uses the short collar for the Mod Hollands. I get only a few rotations of the suppressor on my spec Mod1, yet like 2 or 3 times as many on a complete PRI ModH upper.
 

m1marty

The Bad Guy
Belligerents
Oct 14, 2004
147
94
34
Tacoma, WA
I think PRI uses the short collar for the Mod Hollands. I get only a few rotations of the suppressor on my spec Mod1, yet like 2 or 3 times as many on a complete PRI ModH upper.
What barrel on your spec rifle (I'm assuming Douglas)? I seem to remember there were some variances in the step location between different manufacturers causing the short turn amount issue.
 
  • Like
Reactions: TexasBJ40

TheGerman

Oberleutnant
Belligerents
Jan 25, 2010
5,335
5,647
219
Out West
It's a Douglas. Maybe thats the difference?

I remember calling and ended up talking to Kevin at HCS about it and he explained this was normal for the difference between the 2 rifles. I'm guessing that may be the issue you are mentioning. Can just compare the two collars side by side and find out.
 
  • Like
Reactions: m1marty

FatBoy

Chris Hayes, Nashville TN
Belligerents
Jul 29, 2001
1,179
678
219
45
Nashville, Tennessee
After speaking with Ron, I recall 2-3 turns was about average with the SPR barrels that Gene Barnett originally did for the trial program and that shoulder distance became standard on the mod0s.

After that conversation I moved my shoulders back a touch, maybe .1" or so and now I get 8-10 turns on each rifle. Maybe it makes no difference but I like having more thread purchase.
 
  • Like
Reactions: m1marty