Odd variances in 12-ga. shotshell length

[Murphy4570]

So I was doing some research on a reproduction M1897 Winchester shotgun I have, and all sources were saying it has a 6 shell magazine capacity. This I found odd, as mine holds only 5 shells.

So, I started tinkering. I found that the 00 Buck shells I have are noticeably longer than the target shells I have. The other two shell brands I have will fit 6 into my shotgun, though is a tight fit. Feeding doesn't seem to be affected for the sixth shell.

So I took some measurements. All shells are 12ga, 2 3/4 advertised shells.



Test subjects (left to right): Remington buckshot, Federal target load, Winchester target load.

Specifics:

Remington:
1325fps velocity
9 pellets
00 Buckshot

Federal:
1200fps
8 shot, 1 1/8 oz

Winchester:
1300 fps
1 oz, 6 shot

The Remington buckshot is longest, averaging to 2.3214" long. Winchester's averages to 2.2988", and Federal's averages to 2.2866". Averages were computed from measuring 5 shells in each group.



Remington's had a length ranging from 2.314" to 2.333". Winchester's ranged from 2.314" to 2.287". Federal's ranged from 2.283 to 2.297".

The most consistent length was found with Federal's, with two at 2.285" and two at 2.283". The other two brands were more varied in length.


This data raises some questions.

Is shot shell length dependent upon load type (eg buck vs target vs bird etc)?

Why are shells advertised as 2 3/4" length, yet in reality are much shorter? After all, math is math is math, and in every other part of the world, 2 3/4" = 2.750".


Practical lessons learned:
A repop shotgun will fit its advertised shell amount, but only with certain brands and types of shells.

 

[Onmilo]

Shell length is determined from uncrimped hull.
Length varies with load and type of crimp used, go measure a roll crimped slug load now.

 

[oneounceload]

FIRED length is the length listed - why you need to be careful with older guns where the chamber might be 2-1/2, 2-9/16, 2-5/8 or similar. A 2-3/4 unfired will fit, but when fired, the crimp opening into the forcing cone can raise pressures to unsafe levels.

BTW, a 3" shell will fit in a 2-3/4" only gun, but the same danger as above applies

Shell length has nothing to so with charge weight - it is manufacturing tolerances - remember these things are made on high-speed machinery at incredibly fast production rates. Variations of a few thousandths really doesn't matter

 

[4thPointOfContact]

The only problem I've found with the varying shell lengths among manufacturers has been in how many fit in a magazine tube. For some reason all the Mossberg tubes I've tried seem to be a bit on the 'tight' side. I could fully load 7 ea. 2.75 Winchester shells, but only 6 ea. 2.75 Federals. Seems that with the Federal being >.< longer, when you add it up enough times >......< is just enough to keep that last shell from feeding.

Switching to a different spring cleared that up, but it is something that may have to be taken into consideration.

 

[303tom]

My Model 97 will hold 6 in the mag. 6-2.5 in. shells , the 1897 is a 5+1 , 2.75 in. shells !