I have a customer who inherited a revolver, he is unsure of age or type of ammo that was used.

barrel reads 45 CAL. SMITH AND WESSON
inside reads 59545 or 59646 appears to be an A or 4 down below this number

Serial number 143546 or 145546

Springfield Mass

Any help would be appreciated, he said he had some 45 acp that he placed into chamber but they appeared to be too short. He has not fired weapon because he wasn't sure if ammo was correct or not.

Try .45 Long Colt

An unaltered 1955 will chamber and fire .45ACP with or without moon clips. This one has possibly been reamed out to .45 Colt. If so, it should still handle .45ACP in moon or half moon clips.

When in doubt, take it to a gunsmith.

Not correct. The shoulder in the chamber is there for headspacing purposes. However, since SAAMI sets the specs for cartridge dimensions, the shoulder is placed at maximum case length depth for a given caliber.

My experience has been that any factory ammo or brass, when new, is always considerably less than this dimension - meaning that, in reality, headspacing on that shoulder, by the case mouth, seldom actually occurs.

What does happen is that variances in chamber roundness, smoothness, cleanliness and other variables, will hold some cartridges firmly enough that a firing pin strike will ignite the primers. Others are driven forward in the chamber, which results in a light primer strike and a failure to ignite.

Just as some rounds are held tightly enough for ignition and others are driven forward, some cases may drop out of the cylinder from gravity, while others may be "pluckable" and yet others will have to be poked out using a rod.

You should consider moon clips essential for any revolver that is chambered for a rimless or semi-rimmed round.

Some of the older model 25's and pre-25's may have shorter chambers since SAAMI was not founded until 1926 and I have no idea when S&W adopted their case length dimensions or what they used prior to that - still, clips should always be used.

Unless modified by a previous owner, the chances that it is chambered in .45 Colt are pretty slim - there were some, but they are very rare.

There should be a letter preceding your serial number. If it is an "S" the gun would date from 1955 or 56. If it is an "N", it would date from 1973. Both dates precede the introduction of the 25-3, 4 or 5 which were the commonly available early .45 Colt models.

Measure the depth of the chamber from the back of the cylinder to the step where the throat starts and compare that dimension to the dimension of a .45 ACP case, measured from the extractor groove to the case mouth. They should be similar if it is chambered in .45 ACP - which is the most likely.

Good luck with your new acquisition.

Adios,

Pizza Bob

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NRA Benefactor Member

There is an S prior to serial number, I will get him to bring back and we will measure as suggested. I believe it has moon clips (not sure if full or not, will verify that as well). I do believe he said the diameter of a 45 acp was correct it was the length of the casing which seemed too short. We will research further, thanks for suggestions.