One Quarter Inch ...

[RMc]

Thought I would post this here as many shotgunners are not aware of the length difference between crimp types with birdshot or buckshot loads.


The average case length needed is .40" for folded crimp vs .15" for rolled crimp.

So just a bit of illustration:

2.50" - .15" = 2.35" Roll crimp 2.50" hull loaded length is 2.35"

2.75" - .40" = 2.35" Fold crimp 2.75" hull loaded length is 2.35"

2.75" - .15" = 2.60" Roll crimp 2.75" hull loaded length is 2.60"

3.00" - .40" = 2.60" Fold crimp 3.00" hull loaded length is 2.60"

[Cap'n Morgan]

One quarter inch... Sounds about right. I believe the shift from 2.50" to 2.75" hulls happened because of that newfangled folded crimp - star crimp, we call it over here. The original hull size was probably more or less dictated by the larger volume of black powder and the quality of the wads back then; A relatively thick wad was needed to compress and seal properly. Nowadays, a 1-1/8 ounce load, using modern plastic wad, could easily fit in a 2" hull with folded crimp.

[SuperBlazingSabots]

Greetings, with due respect to RMc, that might be good for shotshell loads but for slugs we need a little more crimp depth for better combustion.
Take a good look at the Brenneke slug known for delivering good results:
https://imgur.com/A16VW8J
We all, who take slug loading seriously are a dedicated family, who have taken it upon ourselves to perfect our tech. We experiment to find better techniques and share our knowledge knowing the components are not specially made for us slug shooters, forced to make do with sub standard parts to load our Heavy slugs etc.

Best regards,
Ajay Madan
Super Blazing Sabots

[RMc]

One quarter inch... Sounds about right. I believe the shift from 2.50" to 2.75" hulls happened because of that newfangled folded crimp - star crimp, we call it over here. The original hull size was probably more or less dictated by the larger volume of black powder and the quality of the wads back then; A relatively thick wad was needed to compress and seal properly.

Indeed, 2.5" roll crimp shotshells were the "standard" in England about the time when star or fold crimps were first experimented with there. A 2.75" hull with a fold crimp maintained the same internal volume, (assuming the same basewad height), as the 2.5" Roll Turn Over crimp).

[RMc]

Greetings, with due respect to RMc, that might be good for shotshell loads but for slugs we need a little more crimp depth for better combustion.
Take a good look at the Brenneke slug known for delivering good results:
https://imgur.com/A16VW8J
We all, who take slug loading seriously are a dedicated family, who have taken it upon ourselves to perfect our tech. We experiment to find better techniques and share our knowledge knowing the components are not specially made for us slug shooters, forced to make do with sub standard parts to load our Heavy slugs etc.

Best regards,
Ajay Madan
Super Blazing Sabots


It appears you have overlooked my specific reference to small shot and buckshot.

The post addresses the oft misuderstood relationship between loaded length and the comensurate available load volume of differing shotshell hull lengths and crimp types. This assumes the same type hull construction and basewad height.

[SuperBlazingSabots]

Greetings RMc, sorry about that mistake. We slug shooters face this issue having to make do with shotshell components which do not always meet our requirements. I was trying to change that and at that time did not have to worry about paying bills and putting food on the table, I was only catering to develop ideas for us slug shooters.

Today, I'm just trying to survive my retirement but have a lot of information that was gained through field testing.
Best regards,
Ajay Madan