History - 1865 Burnside Spencers - Please help with information

[Herbert]

Sorry, can see it was confusing. It was in the question of sling swivels that I ment to refer to the picture.
The cartridge question was because my emtied cases stil has the "bullet crimp", and it might be because they were too long 1.22" (31mm). I use shortened 50-70 Starline.
What is the correct length?

even though the 1865 Spencer is supose to have a front sling swivell you seldom see one fited,i have wonderd weather the front swivel was a opnal extra for the artillary ,the british yoused this systome

[minerotago]

Two FLints

To suppliment my Spencer in the rifle rack and to keep it good company I have purchased a Sharps New Model 1863. The bore is absolutely 'as new' perfect in every aspect. It has little original finish on the exterior but nice condition overall.
My questions which i hope you may be able to answer is - can you tell me to whom it was issued and its history - its serial number is C' 2587
I also  note that on the left hand side of the action there are no markings and I have seen markings in all photos of these rifles on the left hand side. Have you any idea why my carbine may not have them - it has the Sharps and Lawrence patents on the lock, the Lawrence patent on the rear sight and the barrel is correctly marked but so lightly as to be nearly unreadable.
It is also converted from percussion.

Any help you can give me would be greatly appreciated - one day I hope to be able to use both the Spencer and the Sharps on my property to shoot a pig or two as I do much prefer to hunt with the older rifles but out here the Spencer is moreof a logistical problem..