Help needed with Armi Sport Spencer Carbine 56-50 BP load accuracy

[Good Troy]

I bought a used Spencer Carbine from a reenactor last year.  I've had fits getting good groups with it at 50 yards (not messed with any less yardage).  From a clean barrel, the first three or 4 rounds are near point of aim.  Then, it begins to string low and right and finally settles about 6" low and 6" right.  Clean the barrel, and it repeats. 

I've free-floated the barrel.  The only place the forearm touches the barrel is at the point where it is screwed to the barrel lug.  I can easily pass a dollar bill between the forearm and barrel, even when the barrel is very hot.

I'm convinced it is either a fouling issue, or the barrel changes harmonics when hot....note the barrel has a chance to cool when I run the cleaning patches through it. 

I'm shooting a 350 gr FP 0.513 diam soft bullet from Buffalo Arms.  It has a single, but large lube grove, and is lubed with SPG.  This bullet is in Starline Brass over 32 grains (by weight) of 3 F Olde Eynsford.  On a good and humid day (typical in Texas) and 21 shots, a patch runs through the barrel fairly easily, but I do get a bit of crud...nothing that is alarming to me.   

I would like to be able to get 21 shots out of it and it hold a decent group!  Any suggestions will greatly be appreciated.

Humbly,
Good Troy
AKA Two Dogs

[El Supremo]

Interesting:
What about the group size and shape once it settles, please?
Photo's can tell a story, too.  If you cannot post them, try emailing to our esteemed Administrator, "Two Flints".  Perhaps he can post them for you.

From a clean, dry barrel, many of my BP ctg guns take three shots to reach zero and consistency.
At 50 yards, the first shots are often one to two inches high and slightly left.
Same, relatively, with my very accurate modern smokeless rifles.

Thanks.
El Supremo/Kevin Tinny

[Good Troy]

 Yes...I would do well to post a picture!  I will post one, but it will be a few weeks.  I'm out of ammo, and have to order more bullets!

I chose not to post the picture of the target from today....it has over 60 shots on it, with three different points of aim for each set of 20 plus rounds.  Some of the groups overlap.  I kept a mental track of it while I was shooting, but it would be impossible for me to segregate the groups at this point for a detailed look.    I'll shot a fresh target once my bullets come in, and I will number the shots to help for a detailed look.

I too have the experience of the first shot from a clean barrel being off, but I've not had one take more than 2 or 3 shots to start to group, nor had one move this much (6").

[pony express]

Have you tried a pressure point at the tip of the forend? You could do a temporary one with shims. Completely free floating isn't always the best.

[Good Troy]

Hmmmm....it is simple enough to try.  Maybe I should get those bullets overnight delivered!

[Good Troy]

Here are the results with a 350 gr FP bullet from Buffalo Arms.  It is lubed with SPG and is over 32 g by wt 3F Olde "E".

All over the map...  

[Good Troy]

Here are the results with APP 3F, same bullet, same shooter, same 50 yds...
The circled shots are at a different point of aim than the clouded group of shots.
I can live with this group....but the traditionalist in me wants to shoot black powder...Maybe try some Swiss?  2 or 3 F??

[El Supremo]

The bullet holes are square so it seems that you are almost there.

I prefer 3Fg Swiss because it is approximately 15% stronger than GOEX.

Try varying your charge one and two grains higher with up to 1/16" compression.

The case's grip on the bullet must be consistent.  Be sure your case mouths are not brittle.
Annealing by dipping in olive oil and then in molten lead at around 720 degrees will return them to optimum elasticity.  No need to quench brass.  

Changing primers might show promise, but Win LRP's have always worked for me.

Good eyes and consistent bench technique play a part.  
Don't look at the sights for more than five seconds without blinking to relube the eye and gaze away to avoid burning in the image.  
Focus on the front sight and be sure the sliver of white between the bull and post is uniform.