Muzzle Loader Scope Mounting Information

About a year ago I put together a 45 caliber "slug gun" with a gain twist, 1.5 inch across the flats barrel, good lock a trigger and after much searching I was able to get a Unertl scope for a bit less than an arm or a leg! Since it was the large diameter model I had to buy taller mount blocks and did the drilling and taping of the mount holes w/o issues. A month ago I had the rifle out to 200 yards and noted the groups were 5 bullets nearly touching but about 4 inches right of center. I tried some additional scope adjustment but the tube of the scope was touching the left side of the rear adjustable mount. So I pulled the barrel off (hooked breach) and unmounted the scope and front and rear mounts. I used a pair of calipers beside the mount blocks and the ear was fine but the front was leaning a tad to the left!


I pulled the front mount block and checked the squareness of the block bottom and it was ever so slight off causing a lean and also causing the screws to bend slightly. I took a very light skim cut on the bottom and now the block is true. I remounted all and checked the scope cross hairs and now they were not plumb so I adjusted them so they are vertical and horizontal. My neighbor's garage has a very nice seam running both ways with I checked with my iPhone level and they are true. I bore sighted to 100 yards so it should be good?


So yesterday time to try the scope fix and after 4 or 5 shots I was now centered on the home made shoot-n-see and the scope tube was also in the center too which made me happy. My mistake was not checking the vertical of the blocks while I did check the bore sight and cross hair plump but now I now better. I tried moving the scope adjustment two clicks at a time both vertical and horizontal and the bullet impacts were right on the marks!
John

can you tell more about your barrel and load?
I am putting together a slug gun also.

The barrel was bought from another shooter in our club and he had it for 15 years or so. He bought it from one of our real old timers who doesn't remember buying it but said he thought he had it for 12 to 15 years? His name was on one of the barrel flats so someone had made it just for him! It is 1.50 across the flats, no taper, gain twist starting at 1 in 20 and ending at 1 in 15 twist. It has a false muzzle and bullet starter. It has a hooked/patent breach and the tang is very long. The rifling is 8 grooves that are wide and only .002 deep very similar to what Pope did. Bullet starter and false muzzle look like his also. There is no info anywhere on the barrel or breach plug to tell who made it!

The load is 80 grains of Goex FFG with a .060 fiber wad just sitting on the powder that is put in with a drop tube. The bullet is a BACO Creedmoor 540 grain grease groove bullet, pure lead, that I hand lube with Bore Butter just before loading. I was using Doug Knoell's lube and doing a bunch at a time but he has honey in the lube and I found that mice like it and two winters ago chewed the lube out of the bullets and roughed them up!!! The lube idea is working well, no leading or anything and I clean with the 3 part cleaner until the patches are clean, then use a couple with Rem Oil and them wipe with a dry and finally a couple with Bore Butter to season the bore.


I don't know who made the barrel but looking at it with my bore scope showed it is like a mirror inside even after sitting for nearly 30 years? A couple people told me it was a Pope barrel that he never sold and another told me it was made by Numrich but I called them and they said no, they never did any thing like that? So I just enjoy it!
I have several other slug guns I made in the past few years, one is an under hammer and it has a Green Mountain 1 in 18 barrel and it used 90 grains of FFG and shoots just as well at 300 yards with tang sights. Another is a Pecatonica River Schuetzen kit that also has a Green Mountain 1 in 18 barrel, same load as the first one and shoots about the same as the first two I mentioned. I plan to try to vary the powder load some next week to see what results I get. I tried dropping the under hammer load and accuracy went to hell so back to 90 grains so I'll try a bit higher. Hope this helps some as I really like the experimenting once the gun gets together.
John

I got the Allen Foundry under hammer, with a 32-40 barrel blank. it is .314/321" 1:14 twist.I been experimenting with paper patch .308 bullets, and a couple others.
havent got a tight group yet, but it is still a new barrel

When you say .308 bullets, is that the diameter and are they muzzle loader pure lead bullets? Who made the barrel and is it a regular muzzle loader barrel? How tight or loose are the bullets when you insert them and what powder brand and load are you using? If it were me I would start with grease groove bullets and then once the gun can shoot less than 1 MOA and what distances you can shoot at then try the paper patch bullets. Paper patching adds an extra level of complexity to the shooting of muzzle loader cast bullets and that is a hard way to start. I have 5 slug guns and have gotten only one of them to the point where I can shoot paper patched bullets as the powder load is different, sight settings are different and so on. With the Pedersoli Gibbs I use their bullet w/o a wad and shoot just *** they recommend and it does pretty darned well. Some of the world class shooters do shoot that rifle with paper patched bullets but they have way more experience than I do!
John

Good fix on the mounts. That was the trouble with external adjustable mounts (and long tang sights). They had to be treated with care or they would bend or break.

I am about to commit a major sin and drill/tap my Lyman for a scope. I am frustrated with my eyes when shooting peep sights. The groups reflect how poorly I see the target, not how well the rifle will do.

Especially frustrating cause I then pull out my centerfire rifle and put 5 rounds into one largish hole (12x on one and 25x on the other).

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Originally Posted by oldracer

When you say .308 bullets, is that the diameter and are they muzzle loader pure lead bullets? Who made the barrel and is it a regular muzzle loader barrel? How tight or loose are the bullets when you insert them and what powder brand and load are you using? If it were me I would start with grease groove bullets and then once the gun can shoot less than 1 MOA and what distances you can shoot at then try the paper patch bullets. Paper patching adds an extra level of complexity to the shooting of muzzle loader cast bullets and that is a hard way to start. I have 5 slug guns and have gotten only one of them to the point where I can shoot paper patched bullets as the powder load is different, sight settings are different and so on. With the Pedersoli Gibbs I use their bullet w/o a wad and shoot just *** they recommend and it does pretty darned well. Some of the world class shooters do shoot that rifle with paper patched bullets but they have way more experience than I do!
John

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.308 molds, drop at .311, soft, with a paper X patch, 40gr FFFg