Air Gun Home :: View topic - designing a 22XX repeater breach, mechanism pics on page 2

dogon1013 · Member

I'm thinking about designing a repeater breach for the 2240 that is currently in the mail. But I only have 1 pellet type to measure.

Just wondering what common lengths of pellets do you want it to work with. If I get it working, I do plan on selling some. I know there was another one available here: http://www.bryanandac.com/2240.htm but my idea should improve on it.

Still going with the tubular magazine, but spring loaded ideally. It should also automate the chambering, by allowing you to just cycle the bolt normally, instead of the extra steps needed for the above linked model. I also want to make it adjustable for different length pellets. (which is why I am asking for pellet lengths).

I'll post some pics of the design once it's closer to looking like a real breach. (after I get my 2240 and draw some of it up in 3D)

fritz · Silver Status Member

I know that Predator (the hollowpoints with a plastic tip), are pretty much the longest pellet available in small calibers. EunJin pellets designed for HIGH powered Korean airgun are sometimes used in heavily modified Crosmans for increased energy. These EJ's are also quite long.

If the magazine will work with JSB, Predators, and CPH, it will sell.

dogon1013 · Member

any chance someone with those pellets could measure the length of them? I'll order some myself, but I'm curious if any of them are similar in length.

Pointed pellets will probably cause problems (like the predator), but there may be ways around this in the design of the magazine.

EDIT: Does CPH mean Crossman Premier Hollowpoint?

jlwilliams · Veteran Member

Even if it works best with flat nosed pellets, it will still be in demand. The ability to make the most customised pellet gun plarform into a repeater will sell and sell well.

rsterne · Moderator

Here are some lengths for the longer of the common pellets:

JSB Exact Heavy 18 gr. - 7.7 mm
Crow Magnum 18 gr. - 7.7 mm
JSB Stratton (Pointed) 14.3 gr. - 8.0 mm
H&N Silhouette 16 gr. - 8.1 mm
H&N Baracuda (Beeman Kodiak) 21 gr. - 8.5 mm
H&N Rabbit Magnum 25 gr. - 8.6 mm
RWS Super Point 14.3 gr - 8.6 mm

EunJin Domed 28 gr. - 10.0 mm
Predator Polymag 16 gr. - 10.3 mm
Predator Big Boy 26 gr. - 10.6 mm
EunJin Pointed 32 gr. - 12.1 mm

Other than the Predator Polymag, the pellets in the second group are likely too heavy to work in most 22XX based platforms.... with the exception of a highly modified PCP conversion.... There is a competing rotary Magazine available to fit the Disco and 22XX platforms from:

http://qbmags.com/index.html

Their magazine is designed for pellets up to 8mm long.... much longer and there won't be room in the breech for the magazine and bolt probe.... but it would be nice to be able to handle 9mm pellets at least.... Rolling Eyes

Bob

dogon1013 · Member

Thanks for the info.

Anyone know why the Brianandco repeater isn't available? Did it even sell at all?

I've seen the rotary magazine add-on, but you are limited to manually indexing the magazine each time you load. but the disc mag's are removable which is nice, so you can have a few allready loaded with you. Plus, since it's an add-on to existing breaches, I can see why you are limited to short length pellets.

so far the design is a non-removable tubular magazine above the bore. this will naturally make the scope dovetail higher than normal, but not too much.

jlwilliams · Veteran Member

Sort of like the Crosman 400 only on the top?

dogon1013 · Member

jlwilliams · Veteran Member

Cool. Watching with interest.

AirGunEric · Site Admin

broommaster2000 · Moderator

The Hatsan AT 44-10 uses quite a brilliant simple system. It's sold as the something something Halestorm in the states. Have a good look at it if you can. Neutral

dogon1013 · Member

found the Hatsan here: http://www.hatsan.com.tr/at44s_10.asp
looks like a rotary magazine, and I think it's sold as the air venturi halestorm here in the states.

I want to stick with the tube magazine for now. It has a few advantages over the rotary. It's easier to increase capacity (just lengthen the tube). it could theoretically feed several different lengths of pellets, without swapping parts. It will also work better with my auto loading idea.

the mechanism I have in mind is similar to a pump action shotgun but with the magazine above the barrel. (In fact I was thinking of adding a "pump" forend to it if it works out.)

dogon1013 · Member

got my 2240 in the mail today, and started drawing up parts.

Here's most of the basic 2240 mechanism:

rsterne · Moderator

Man I'd love to have a CAD program and the know-how to use it.... Mr. Green

Bob

broommaster2000 · Moderator