doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com 2 1/2 " 20 ga. data

Does anyone have a good source for load data for 2 1/2 " 20's or lower pressure 2 3/4. Thanks, Mark

Here is the lowest I use.

2 3/4 Federal Plastic Target Shells 7/8 oz 1,200 CCI 209M Herco 20S1 wad 17.5 7,600

http://alliantpowder.com/reloaders/powderlist.aspx?type=2&powderid=6&gauge=20

Mike

fun reading

http://www.nssa-nsca.org/wp-content/uploads/2011/04/SSR/cerettos.pdf

Per Lyman's 5th Ed.:
16gr Unique
Cheddite hull
Win 209
Win WAA20 wad
1185 fps/7,200 psi

17gr 800X
Cheddite hull
Rem 209P
Rem RXP20 wad
1200fps/6,600 psi

17gr Solo 1250
Fiocchi hull
CCI 209
Win WAA20
1201 fps/7,100 psi

Here is one from the IMR website that I have used and is very similar to Ham's second load. A bit dirty but it never bothered me.

AA hulls
IMR 800-X 16.5gr
Rem. 209P
Rem. RXP 20
7,500 PSI
1,200
7/8oz

PM sent for address to send spreadsheet to

Note any 2 3/4 load that will fit in a 2 1/2 ich hull (mostly 7/8 oz and a few 1 oz loafs will)

I have found the federal hulls good for low pressure loads and that under 8,000 PSI should be acceptable as a cut line.

Mark: Remember that if you're using 2 3/4" hulls in a 2 1/2" chamber, you need to build in an additional margin of safety. Sherman Bell's tests with longer hulls in shorter chambers showed that you can get an increase of 1,000 psi vs the same load fired in a 2 3/4" chamber. I'd agree that generally speaking, 8,000 psi "book value" is probably a good place to draw the line. That'd mean 9,000 psi factoring in an extra 1,000 psi for the longer hull.

Also remember the average 2�" 20 gauge chamber measures 2�" to the cone. Most 12 gauge so called "2�"" chambers actually measure either 2 9/16" or 2 5/8" thus have a bit more clearance from the end of the loaded shell to the cone than does a 20. This clearance beyond the shell is what allows the crimp to unfold without a pressure rise. Since that "Additional 1,000 psi" with the longer hull was not consistent, but occasional, I have grave doubts that Bell ran sufficient tests to establish an absolute that it was the result of the shell length vs chamber & not just a normal variation from shell to shell. Within a given number of shells that much variation is certainly not unusual.
It has been "Said Many Times, Many Places" but I will say it once more "Never, Ever" fire a shell in which the "Loaded" shell end is pushed into the cone. This puts extra resistance on the crimp's unfolding & can create a rapid pressure rise.

I shot some 2 1/2" reloads at the skeet range today
Herco and 7/8 ounce, and RST hulls, all loaded on a PW 375.
What fun, what fun
Mike

Mike,
Is Herco still available or discontinued?

I use to use it in my 28ga loads but can't find it anymore and have gone to Pro Reach. Nice low pressure numbers.

If the shell is cut down from 2 3/4 to 2 1/2 then no additional pressure factor need be considered, given the 2 3/4 fits the data is acceptable in the 2 1/2 inch chamber. I use the general limit of a projected PSI no greater than 8.000 PSI as my limit, though I am probably being too conservative. That said we all determine our risk tolerance levels.