High Caliber Sales MK12 Mod1 at the range

[alan98]

I sent off my 308 to GAP for a rebarrel so I've been shooting my HCS MK12 Mod1 lately. This thing sure is fun!!! I still need either a NF or Leupold correct scope, but for now, I threw on my NF 5.5-22 mil/mil. I've been testing the load with win brass and 24.2 varget under a 77 SMK. I tend to pull the last round sometimes!

The one pic is 100 yards 8 rounds and I pulled the ninth one. Around .55 center to center for the 8 rounds. The others are shooting a steel plate at 500 meters. 6 rounds on the one and 7 on the other..pulled the last one again! lol. Anyways, just thought I'd share some pics. These groups were fired rather fast but I'm extremely pleased with it so far!


Alan


I shot it again at 500 yards tonight.Groups were pretty good with one being 2.4" for 6 rounds. I shot 3 foulers..then 3 groups...two groups 6 rounds, one group 7 rounds..driving down each time to check and paste over them. I kept the scope dialed the same for all. The last group of 7 rounds, the wind changed as can be seen in the pic. Overall it's very consistent as can be seen in the pic, especially the first 3 groups for a total of 19 rounds. 17 of the 19 in first 3 groups in 2.5" vertical. 21 of 26 for all rounds total in 2.5 or less vertical spread.

 

[MontanaKid]

Looks good. Does HCS usually keep their MK12 uppers in stock, or is it order and wait for it to be built?

 

[titom110]

Looks good. Does HCS usually keep their MK12 uppers in stock, or is it order and wait for it to be built?

Mostly on an order and wait process.

 

[Km22]

When they do have the parts, it only takes a couple weeks to build.

 

[vereceleritas]

I believe the availability of the Douglas barrels is the limiting factor to how many they can make.

 

[alan98]

Best thing is to call or email Kevin at HCS and get put on the list if you want one.

Alan

 

[muggs13]

25.2 sounds like a lot for Varget. I thought I was pushing it at 24grns for the 77smk. What are the specs on the load you are using?

 

[alan98]

24.2 Varget...Guess I missed that when I read through it. My bad!! I'm using 24.2 Varget with 77SMK, Fed 205 primer and Win brass. Yea I wouldn't wanna try 25.2 grains

Anyone else tend to pull the last round when shooting an auto? I'm not sure if it's me trying not to screw the group up when I know it's the last one and pull it, or the difference since the bolt locks back last round.

Alan

 

[LRRPF52]

Hornady's 8th Edition, with a specific section for service rifle AR15 in .223 Rem lists 23.5gr of Varget as the max underneath the 75gr BTHP, using a Winchester Small Rifle Primer at 2.250" COL, using a Winchester brass.

8208XBR is a great powder for the .223 Rem, temp-stable, gives good velocities. I was really impressed with it and the Hornady 75gr A-MAX from a 16" gun, running 2700fps. Needs a little bit of taper crimp on the neck with the A-MAX barely fitting in mag length though. Accurate as sin in heavy, full-value winds and 17F temp.

 

[buckjay]

Looks nice. I have a 18" SPR build coming up and I can't wait to see how it performs.

 

[alan98]

I added a pic of 4 groups shot at same target at 500 yards..pretty consistent just some windage change especially in the last group.

Alan

 

[MSTN]

It may not be you pulling the last round. I've noticed over time that the last round from some (not all) magazines using some (not all) uppers tends to fall out of the group.

One sure way to test yourself is to load more rounds in the magazine than you plan to fire in a particular group.

I would not use your best ammo to round out the bottom of the magazine. Even if you do not fire the last round chambered, cycling it through the action will undoubtedly leave the usual two scratches in the jacket from being dragged by the ejector and extractor in unison over the sharp corners of the feed ramps. Also, match grade commercial ammo loaded without a crimp gets knocked out of concentricity (up to 0.003"!) with alarming regularity just getting beat up while being chambered in an AR'. Luckily, there's a fix for this ....

 

[alan98]

Cleaned the barrel and had a good 6 round group at 300 yards yesterday. 1.5" 5 were in around .83". Also included a 4" 5 shot group at 600 yards. Just confirming the load again...its good to go, just the wind get you more with the 223's than I'm used to

 

[Kletzenklueffer]

David Tubb posted here a long time ago about the first and last round feed from a semi and the impact shift at long range. My recollection is that it's related to the different feeding characteristics for each round (first being manual bolt release, and last being the bolt not closing or feeding another round).

A solution is simply to shoot for groups in the middle of the mag and consider the first and last foulers.

you should still track first round (CBS) impact data for that cricital shot placement.