Crosman 2289 backpacker mods for power

M

marcjer

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Hello fellow CGNers,

any suggestions on how to optimize power (without too much loss in accuracy)
on a Crosman 2289 backpacker ?

ex:

1. Flat top piston & valve replacement.

2. 24 instead of 14 inch bbl



With those who own crosman, is replacing the breech worth it? ( to mount a scope). The breeches I find online are more expensive than the gun!!!!
I am thinking of getting 2 of those little clamp on mounts instead, but will reconsider if CGNers have some valuable pointers.


Hoping to make this a gun capable of taking squirrels from 15-20 yards.


Thanks.
 
I wouldn't bother with the 24" barrel as 14" will shoot over 500 fps with the FTP.It will certainly kill squirrels and rabbit sized game out to 30 yards.A buddy uses his on crows.Harold
 
Thanks

Much appreciated suggestions.

One of the key advantages of the backpacker is the fact it is compact enough to fit in your backpack ( hence the name "backpacker?").

Soooo.. if I can get away with out the 24 in" barrel, I'll opt out.

I read that there a good 5-10 fps per inch of bbl up to a point.

I'll check the other related forums.

Any other suggested mods would be appreciated.

Thanks
 
have you checked the crown on the barrel? If it's even, then don't worry. But if it's a little off a good polish or a spin in a lathe will gain a noticable amount of accuracy.

Drilling out the transfer port to 11/64 then stepping it up to 3/16, installing a small piece of aluminium 3/16 OD tubing in the barrel and drilling a corresponding hole in the valve body will help seal things up. You may not gain a great deal of power, you're more likely to gain shot to shot consistency by not loosing a random amount of air each shot. The rubber o-rings and the little brass transfer port are horrible.
 
You may want to bear in mind that the 2289 Backpacker is classified as a HG. If you make it go over the 152.4mps/5.7 joules (500fps) threshhold you will have created a restricted firearm.
Might be worth a call to CFC to make sure you stay out of trouble.
 
If you create a restricted firearm you are subject to the same registration issues as a powder burner.
 
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Thanks good advice.. I got the impression that there was a bleed hole in the tube where the hammer and stem of the valve meet, which prevents it going over 495ft/sec. I don't think my current one goes even close 300ft/sec.

Thanks for the advice.
 
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I know this is a bit off topic, but my 1377 Crosman, is deadly on squirrels, out to 15 or so yards.It's such a good deal, that it is good to have as well. Mine is completely stock..Don't get that goofy Crosman scope mount.If you go that route, get the steel breech, that is grooved for a scope.
 
Interesting Harold. How many pumps to achieve 600fps ? While I don't have access to a Chrony to verify, I would think that the Canadian's version of 495fps is an overstatement.

The size of the bleed hole at the back of the valve is loosely 1/3 to 1/4 the size of the connection to the chamber.

I'm no physicist, but assuming that hole was plugged, I would guess that an extra 1/3 or 1/4 of the air pressure would actually push the pellet.

So if the Can version is designed for 495 at 10 pumps, then I'd guess that the US version is 1.25 to 1.33 more powerful at least, which would be over 600fps.

I wonder how much pumps the US version can take before the seals get damaged?
And what kind of power that would generate.

Nevertheless, I am not going to experiment with my own pumpers, because I respect the law like a good Canadian should.
 
marcjer said:
Thanks good advice.. I got the impression that there was a bleed hole in the tube where the hammer and stem of the valve meet, which prevents it going over 495ft/sec. I don't think my current one goes even close 300ft/sec.

Thanks for the advice.
Click to expand...

That is correct. The Canadian version has the hole. Instead of filling it you can just get the flat-top piston with a new valve without the hole.

scopesandammo "dot" com is a very good place to get what you need. I also reccomend Jim Giles at crookedbarn "dot" com for anything Crosman related. He mainly works on CO2 guns but has ambi breeches for sale that will fit a 2289 and all of his breeches have two barrel anchor screws as opposed to Crosman's one.

Another thing to consider; if you wish to increase the barrel length you might want to look into increasing the volume in the valve body as well as the diameter and shape of the release hole as well.

To accomplish this, you can remove part of the threads on the lower / rear part of the valve body and / or remove some metal from the inside. There is also a mod for the spring which relocates it outside to gain more room for air.

Doing these mods will allow you to optimize a greater number of pumps and also allow for enough expanding air to accelerate the pellet all of the way down the barrel.

From personal experience, with a valve without the bleed hole; I never saw much of a velocity increase beyond an 18" barrel and had a significant drop with a 24", no matter how many pumps I gave it.
 
Be careful modding the 1377 with the flat top piston. It will make it into a restricted firearm. Stupid law yes, but law nonetheless. The Canadian 1377 I have shoots at 360fps at 10 pumps and maxes out at 385, all with 7.9 grain crosman pellets, giving just over 2.5FPE! The US forums report the stock 1377 shooting anywhere from 515 to 555fps, so even without an FPT it would certainly shoot over 500fps.

The workaround is to either get a 2289 pump tube and transfer the components onto that, making it officially a rifle (serial number is on the tube and belongs to a rifle as I read on the canadian airgun forum), or get the 2289 and put the supplied pistol grip on. You now have a non-restricted rifle. Trying to get it registered is another matter, I bet the CFC would be so confused they wouldn't even know what to do. I'm not sure if it could be registered as the S/N would belong to an airgun, not a firearm - how would they put that into the system? (taking a jab at the system here - sarcasm)
Even with a plugged bleed hole, I think the 2289 can still hit 500fps. The US guys report getting close to that at 10 pumps out of stock guns. Is it worth the hassle when you can just pick up a PAL rated springer that will be more accurate? Either way it's fun to experiment.

A 2289 with a 24" barrel, flat top piston and light valve spring will shoot 14.3s at 575fps at 10 pumps and close to 625fps at 15. With a very light spring it will do 600/665 (Yes, that's 14 foot-pounds out of a 2289) at 10/15 pumps but the spring gets too weak to reliably seal the valve and sometimes it won't hold air. With the 14" barrel you're looking at 500fps at 10 pumps, and 550 at 15. My stock 2289 shot at a laughable 355fps at 10 pumps!!!!

For your valve spring, you can use the trigger spring, just compress it completely one time then slap it into the valve - then just get a replacement light trigger spring from Lordco, polish up the sear and you're ready to rock!

Re: scope mounts.
The steel breech is made for the CO2 guns which have a slightly larger diameter tube. AS a result the breech doesn't fit that well on the 13xx/2289 tubes. i wasn't that impressed with the fit. The barrel also fits a bit sloppy in the breech even though there is a set screw to fasten it.

I saw no measurable difference in accuracy between the steel breech vs. the barrel mounted clamps as a scope mount. I eventually put the plastic breech back on my rifle because I didn't like how the bolt wouldn't stay open when the gun was pointed down (there is no friction in the steel breech) and put the iron sights back on. The rear sight doesn't fit on the steel breech, by the way.

In closing, here's a great PDF on power mods, in case you haven't seen it yet. The 1322 is a better platform for power mods as you can get considerably more power out of it without breaking 500fps. Since you're limited in velocity the pellet drop will be the same regardless of caliber. I have an old 1322 that had the little disc to restrict air flow. with it removed it shoots 14.3s at 425 fps. I tried light pellets years ago but I was never able to achieve 500fps.

Anyway, I'll shut up, I hope some of my rambling helps you out.
Good luck!

B
 
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I have a 2289 and love it, HOWEVER, I don't know the extent of the mods. I do know that it has a steel breach. I got it from a guy who owed me money and gave me this instead, which I didn't want until I shot it, now me likey very much. Chrono verified at 550-615fps, depending on number of pumps, pellet brand, etc.

I was always into pistols, but the 2289 turned me on to air rifles, but I like my 2289 so much I can't bring myself to purchase another rifle. It would be nice to not have to pump the rifle so much, but that's a sacrifice I will make, being able to walk half a day, carrying a rifle and barely know it's there. If something ever happens to my 2289, I will immediatley buy another to replace it. +1 on airgunforum, lots to learn over there.
 
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marcjer said:
Hey Gyppo.. don't shut up.. keep it coming.. very good info here. 1322 still in the market?
Click to expand...

Yes, the 1322 is available again! scopesandammo.com sells it.
They state that it isn't de-tuned as the advertised MV is 460fps.

I just ran my old 1322 over the chrony and got 423fps for 14.3CPs and 473fps for 11.9gr hobbys. 5.7 and 5.9 FPE respectively.

So I take back what I said, there isn't much room for legal modding! But don't let that stop you from getting the 1322. Great pistol.

Benoit
 
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