Went to a reduced load due to inconsistencies

[Sparkitoff]

I have a .50 sidelock made from parts given to me. It has a 24" barrel. I put a scope on it for accuracy testing and for my young sons to shoot accurately. Previously I spent the day sighting in with 85 grains T7, 385 grain Hornady bullet, CCI #11 Mag primer. The rifle was set at 100 yards and was keeping nice groups with a good swabbing between shots.

On the range I loaded as described and fired off the bench at the 100 yard target. No hole could be found anywhere on the paper! Repeat.

Instead of messing around, I checked the scope (Leupold IER) by firing a group at close range and it did hold a tight group albut not near the bullseye.

I switched to 60 grains T7, PRB (Hornday) and CCI #11 Mag primer. We were able to obtain tight groups at 25 yards dead on in the bullseye. Two shots at a 50 yard target failed to produce any holes in the paper!

Since my sons are going to use this initially on some exotics out of closed blinds where the range is typically no more than 30 yards, we left the rifle sighted in as such. However, we cleaned fully, repeated and cleaned fully and repeated. It holds that zero just fine. Another day we will dial in at further range.

I got a velocity of 1314fps. While this is far from the velocity potential of the PRB, I think it will be just fine for deer-sized exotics at the close range we will encounter. I'll report back when successful.

Any opinions or advice about the inability to hold previously sighted-in POI is appreciated.

 

[Zonie]

Welcome to the Forum.

Do you have any idea what the rate of twist is in your barrel?
Also, do the rifling grooves seem to be deep or are they shallow?

A barrel made for shooting patched roundballs with its fairly slow (1:48 or more) twist and fairly deep grooves (greater than .005 or, 2 hairs) will often shoot elongated bullets poorly.

As for the 25 yard accuracy, most any rifle will shoot patched ball or elongated lead bullets well at that range.
It's only at the longer ranges like 50 or more yards that the real accuracy, or problems of the load and barrel show up.

 

[BrownBear]

Your description sure makes me wonder about leading, especially if it was shooting well before. If your bullet lube is failing at its job, lead will build up and certainly won't come out with swabbing.

 

[old gunsmith]

I do agree with the possibility of bore leading- Back in the day TC Hawkins with Maxi Balls would lead like no tomorrow and the solution was to scrub them with a bore brush and a lead removing powder solvent. OG

 

[Loyalist Dave]

Sounds like something similar that I encountered.

The conical may not be stabilizing, and has nothing to do with the powder load. Not all conicals work in all barrels, even if the conicals are made by the same company that made the rifle. For example I have a TC New Englander that hates TC Maxi-Balls, but loves the different shape of the TC Maxi-Hunter.
:idunno:

Fortunately, that rifle also loves patched round ball, and in .54, the PRB is plenty for deer out to 100 yards, with my getting them closer to around the 50 yard mark. So I use the PRB as it's very accurate and doesn't beat my shoulder the way the Maxi-hunter does from that rifle. :wink:

I'd suggest you check the twist rate as suggested in one of the previous replies, AND try some patched round balls out too, and see what happens. If the PRB work well, then you have a projectile problem, not a powder load problem. Now this might mean excessive leading so bad the conicals simply aren't being spun right (yet I'd think leading that bad would FUBAR your PRB groups too), giving you "knuckle balls" at 50 yards, but I think it slightly more likely the bullet just doesn't like your barrel and IF you must use a conical, you need to change the style.

LD

 

[mooman76]

Good advice here. A RB is perfectly capable of doing the job but if you are stuck on using conicals a shorter/lighter conical would work better in a slow twist barrel. If you don't know the twist of the barrel you can figure it out easy enough. Mark a ram rode and with a tight fitting jag/patch combo push it into the barrel. i.e. 1/2 turn in 24" equals 1-48 twist.

 

[nhmoose]

I would also make sure the scope mount and rings are still tight.

 

[Vaino]

Had that happen to me w/ Maxiballs in my TC Hawken and the cause was severe leading.....so much so that the rifling looked like it disappeared. A good brushing w/ a phosphor bronze brush finally brought the bore back w/o any leading.

Maxiballs actually don't have that much bearing surface, only the "rings".

This will happen w/ "big" loads that cause the conical to shed lead because it wants to go straight instead of following the rifling....and it gets worst w/ every shot......Fred

 

[Sparkitoff]

Thanks for the replies. The concicals were just an experiment to find a good load. The rifle is 1/48" twist. The PRB are fine and seem to be doing okay with just the 60 grains of powder. May increase powder a bit and see how she goes.

 

[Moe1960]

Welcome to the forum. I would to ask what is the make of your muzzleloader and how did you install a scope. I have a traditions hawken woodsman and would like to put a scope on the rifle since I have problems with open sights. A photo would help..Thanks