doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Another short shell question........

I have been looking at a nice C.S. Rosson 20 gauge for some time now, but I refuse to buy it because it needs 2 1/2 " shells. I see absolutely no place that has them for sale. So, am I going to have to take the gun to a gunsmith to check the chambers and lengthen them if he can? Is that my only option? I would hate to buy the gun and then find out the chambers can't be lengthened. I have a 20 gauge reloader that I reload 2 3/4 " shells, but I don't see any way to get my MEC to make 2 1/2 " loads. That plus I have no empty hulls. What do you gentlemen do when you need 2 1/2 "-- 20 gauge reloads? Thanks for any opinions.

What I do is use low pressure 2 3/4 loads, like B&P Comp 1 at 1160 FPS.
or you might consider having the chamber opened to 2 5/8"

Just me saying, you decide what you want to do.

RST 2.5 inch 20 gauge shells

RST has 2.5-inch 20-gauge, 7/8 oz, available in a variety of sizes for $22 per box. Other option is to cut down 2.75-inch hulls to 2.5 inches, use a MEC 20-gauge single-stage press, and roll crimp instead of the last 2 (crimping) stations, or even get a short kit from MEC so you can fold crimp the short shells.
I have purchased loaded shells from RST and I have used roll crimping for the cut down shells. I bought the short kit but have not gotten around to installing it since the other options have worked well.

https://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=610024

This might solve the problem for you.

Jimmy:

Don't fear the ammo issue. Its simple to solve.

You have a press. Just trim once fired 2 3/4" hulls down to 2 9/16", use an appropriate lower pressure recipe for a 2 3/4" straight wall hull, and add a 20 ga. shot card on top of the shot column before you start to fold crimp. Then load as normal on your press. No adjustments needed to your press. It is that simple.

I'm guessing your best bet is using 20/28, Unique or Green Dot. Longshot is another option.

If you need a cutter, let me know. I can show you how to make one with an exacto blade in a wood dowel that zips right through hulls. Russ

I have been using International Clays when I load 2 3/4 oz. loads and I am about out. (Yeah, the bottle is pretty old, but still works fine.) I have about 1/4 of a one pound bottle left. So, I got a one pound bottle of Longshot to use when I run out a few months ago. My buddies and I can't find any Green Dot around this area. I have been looking on the internet for the RST shells, but every site I found said that they were out of stock. So, thanks for that info, playing hooky. My 20 gauge reloader doesn't have a name on it, but it is just like my 12 gauge Grabber only smaller. So, where do I get the 20 gauge shot cards? (I know I am asking a lot of different questions to do this different ways. I just want to have several options to decide. Sorry about that.) I also use mostly Gun Clubs to reload my 2 3/4 reloads. I have never roll crimped with a card. I never needed to. Also, RWG, I have seen those cutters on the internet. I thought about making one, but I never got around to it. I do goof up my shells and have to take them apart occasionally. So, thanks for all of the help, guys. I'll have to decide and see what happens.

How much pressure spike can be present with plastic shells if the loads are low pressure and low shot load?



















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Your guess is a good as anyone's Bill. Everyone likes to quote Bell's study of 12 GAUGE shells and NO ONE AFAIK as conducted a similar study of 16g or 20g, at least in the last 125 years
https://books.google.com/books?id=inQCAAAAYAAJ&pg=PA280
A trial of 1 1/8 oz. 3 Dr. Eq. 2 1/2” shells in 2” chambers with “an exceedingly long and gradual cone” showed very little increase in pressure.
(1.72 Tons by Burrard's conversion is only 4,660 psi and most period reported numbers for 1 1/8 oz. 3 Drams Bulk Smokeless were 6000 - 8000 psi)

As you know, Parker Bros. cut the 20g chambers shorter than 2 1/2". I had a 1924 20g with 2 3/8" chambers. With AA 7/8 oz target loads the case mouth was feathered and recoil was WICKED.

As often discussed, lengthening forcing cones WILL diminish chamber pressure, and modern 20g nominally 2 3/4" shells are often shorter than 2 3/4".

I don't like cutting down 2 3/4 hulls. As you can see in Drew's picture above there is quite a bit of the star crimp left on the hull. I suppose it may be okay if you are star crimping your 2.5 hulls but they don't form well with a roll crimp. I use 3" hulls for that reason and being I shoot a lot of migratory birds with a good crew I have lots to cut down. What I've done is make a jig out of a 2x4. I planed it to 2.5 inches then cut the appropriate sized holes for the hulls to fit through. Use a fine blade on a table saw and you can make as many as you like in one cut. My jig is good for 20 hulls. I also do the same for plastic wads since I only use the cup when reloading.

Tamid:

My option B above is predicated on keeping some of the existing crimp memory in place to retain the overshot card once the final fold crimp is applied. Its less elegant than a nice roll crimp, but effective for those of us using progressive presses.

I agree with you. If roll crimping, then you don't want any of the existing fold crimp to remain.

Drew:

Thanks for the image of 20 ga. hulls. Makes sense that many would be shorter than 2 3/4" in length.

Agree with your point about relaxing the steep angle of the forcing cones, provided their is enough thickness in the barrels to support the removal. I own a german guild built 16 ga. that had 2" chambers and super steep forcing cones. A 2 1/2" RST would not fit in that chamber. I had the chambers and cones lengthened to solve the problem. Gun shoots great now.