12 guage TC Black mountain magnum shoots low

[bigbore442001]

A while back I purchased a previously owned but never fired Thompson Center Black Mountain magnum 12 gauge shotgun with screw in chokes. I have been playing with it as of late and one thing that bugs me is that it patterns low.

I was patterning on a turkey head target at 25 yards with 100 grains of H777 and 1 3/4 oz of no 6 shot. I placed two felt wads between powder and shot and one over the shot.

If I aim the gun like a rifle with the bead level with the tang( bear in mind most turkey hunters aim their shotguns rather than point as if it were a pheasant being flushed) the pattern is low. If I point the bead well above the tang the pattern is more centered. I know the obvious action is to aim it in that manner but for me it is a little discerning. I would rather aim with the little U notch in the tang for turkey hunting. This gun is going to be used mainly for turkey rather than upland game.

Could I shim the forestock to raise the muzzle? I am not sure if that would work but I will defer to those people with much greater wisdom than I. Thanks

 

[dbutch]

BB..any chance of replacing the bead with a smaller one..had to do this on a 12 ga. new Englander barrel brought the POI up 6 to 8" at 30 yards..or else use the bottom of the existing bead as your focus point. Your other option is to put the bottom of the bead at the top of the turkeys head.

 

[roundball]

This gun is going to be used mainly for turkey rather than upland game.

If it was me I'd either add a rear sight to be able to raise / adjust the POI;
Or, have the barrel straightened to correct the POI;

 

[dbutch]

BB One other idea..add a short raised solid rib on the top of the tang ahead of the top screw.
Solid no notch.just thinking out loud...Dan

 

[Britsmoothy]

Hi BB, for the job in hand for this gun as just mentioned sounds good.

Brits.

 

[vern faulkner]

Shoot at taller turkeys. :blah: :blah: Vern

 

[roundball]

Or keep the same POA but hold the gun upside down
:grin:

 

[bigbore442001]

I am glad to see that there is no end to the jocularity here. :thumbsup:

My fear is that subconciously at the last miute I will compensate and put the bead in line with the tang and fire with the result of a crippling body shot instead of a clean killing head-neck shot.

 

[roundball]

My fear is that subconciously at the last miute I will compensate and put the bead in line with the tang and fire with the result of a crippling body shot instead of a clean killing head-neck shot.

On a serious note, I completely agree...you have to get it right...the old "react like you train" syndrome will kick in on game, and you'll align the sights like you have all your life

I had a new .50cal T/C round ball barrel that would not shoot to center axis of the bore, and sent it back to them...they have a laser guided barrel alignment machine to fine tune align (bend) barrels...I assume they could do that smoothbore barrel as well...might give the service manager a call.

 

[bigbore442001]

After this season I plan to send it back. Here are some pictures of the gun and a pattern taken at 30 yards.

 

[dbutch]

BB... Do yourself a big favor and get big sheets of white paper or white card board..bench the gun and pattern..shooting at a 8.5X11" sheet of paper only gives you part of the big picture.

Minimum 30" X30" apply a center target..pattern and then report back .
You need to see the whole picture.

 

[tg]

I am not familiar with this gun, but can you use the tang bolt to hold a homemade rear sight as needed?

 

[rkmeyer]

Bigbore,
This months Muzzleloader Mag (May/June issue) has an article on a rear peep sight that mounts on the tang for hunting. The sight is adjustable for elevation and is quite simple to make.
PM me with your email.
Dusty

 

[August West]

Dusty,
I'm not bigbore but I PMed you too, I would like to see that sight. Hard to get magazines over here, I live in South Korea. Chris

 

[goon]

Never done this with a muzzleloader, but I did have to modify the bead on a NEF single barrel. I carefully filed it down a bit at a time, then on one side to move my point of impact where I wanted it. I had to do the same thing on a Mossberg 835 once to shift the pattern to the right. Worked beautifully and it was utterly necessary with that extra-full turkey choke.

I personally would try this before I'd send the gun back.