Air Gun Home :: View topic - Getting a little more punch out of a springer.

jlwilliams · Veteran Member

I've never done much work on spring piston guns. I took a Chinese under lever apart a few years ago, cleaned it up and put it back together. Mostly just to get all the crap out of it that they put on them for shipping. I also did a clean up on a second hand RSW pistol (don't remember the model, it was the 'magnum' springer they still sell).

I'd like to try to learn how to tune springers for accuracy, reliability and power. What should I be looking at doing? Accuracy, I'd imagine, is mostly the same stuff as on anything else. Muzzle crown, lapped bore (but not too much), proper bedding of the action to the stock, the usual. But getting more flow through thew powerplant, I have limited ideas. Should I be upgrading seals? Springs?

Any reccomended reading on this?

Any help would be apreciated.

rsterne · Moderator

The best advice I can give you is don't go too far from the original design.... If you want more power, you need a bigger air chamber (bore and/or stroke).... With that, be prepared for more recoil, which means tougher on scopes, and harder to hit with....

I think the best shooting springers are in the moderate power range.... say 14-18 FPE.... Once you go over 20 FPE they tend to be a beast.... While springers exist in the 30 FPE catagory, I'd take a PCP of similar power any day....

Bob

Slavia · Moderator

jlwilliams · Veteran Member

Good points. It's better to hit with 15 fpe than to miss with 30.

One reason I'm looking at getting the most performance out of a given springer powerplant is that I'd like to try some short barrels, and I don't want to lose effectiveness. (I'm really thinking of a few diferent projects, but one of them being a fold up backpacker that doesn't require any gas or backup equipment, more or less a pitol with a foldout stock, and I want it to be able to kill small game)

Maybe a question I should be asking is; how much barrel do I need relative to a spring piston's displacement? I've heard that springers are less barrel length dependant than CO2 or pneumatics, but what I've heard is mostly anecdotal and I don't have much to really base a plan of action on.

rsterne · Moderator

I have never experimented.... but I have heard that barrels down to about 12" are OK for most springers.... They do get harder to cock though....

Bob

kanyon · Silver Status Member

jlwilliams · Veteran Member

Maybe a side lever would be a good platform for that.

domer_pyle · Senior Member

Was reading through some old threads, had to revive this one for a question that's plagued me for a while.

It's said a pellet reaches it's max velocity within X" of the barrel, well wouldn't this be a bit relative to the swept volume of the chamber? I'd assume the 5" travel of my B3-3 piston would cause the pellet to reach it's max speed much sooner in it's travel than the long piston stroke of my XL 1100.

Is there a formula for this? And if so would it just be to find the volume of the compression chamber and do some guess and check work with different barrel length numbers til getting the same number as the chamber volume?

I don't consider myself too much of a noob to AGs but with all the info on here I can't help but ask a lot of questions lol. Curiosity will be the death of me someday.

rsterne · Moderator

Just based on pure logic.... the greater the swept volume compared to the bore volume.... I would think the longer the optimum barrel length.... I kind of think of a springer as working like a PCP running at high pressure and very short valve duration.... A tiny bit of air is compressed and released in a very short period of time.... and in most springers, some combustion is said to take place, adding to the power as well.... This makes perfect sense when you look at the efficiency (FPE produced compared to the amount of air used).... Springers beat PCPs hands down....

The best efficiency I have measured in a .22 cal PCP was 1.92 FPE/CI air used (at 1 Bar).... A Diana 350 (B-28) has a swept volume of only 71 cc (4.3 CI) and yet produces up to 25 FPE in .22 cal.... That is 5.8 FPE/CI.... so clearly something unusual is happening.... whether it's the extra energy created by compressing the air (heat), combustion, or a combination of the two....

Generally, as the efficiency goes up, the need for a longer barrel (to expand the otherwise wasted air) decreases.... However, there still must be a relationship between swept volume in a springer and optimum barrel length....

Bob

domer_pyle · Senior Member

Airgunning and quantum physics: the more you know the less you know and the more questions you have lol. Thanks though that is kinda helpful

Crosman140 · Senior Member

rsterne · Moderator

Crosman 2289 if you can find a good one or existing stock.... Crosman has discontinued it....

Bob

broommaster2000 · Moderator

I cuold recommend that chinese Diana 48 clone. They have some room for experimenting but they tend to be quite pricey. Neutral

The idea being, that a Diana 48 comes with a reasonably short barrel, but with a big action. Technically, it could make for a good Bullpup because it doesn't have a lot of parts under the action.

Alstone · Moderator & Site Supporter

My AirArms TX200HC has a barrel only 9" long and is deadly accrate out to 30m, also the cocking is not to bad.

Al

broommaster2000 · Moderator

I have a friend who also owns a TX200HC, and he puts em' tight past 50 yards!