GTA
Airguns by Make and Model => Crosman Airguns => Topic started by: AirgunHunter on May 18, 2014, 08:20:02 PM
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Well I was going to pick one up a while ago and never ended. up doing so.Picked one up at big 5 yesterday so I am excited!One thing I noticed is that is pretty hard to pump and I have blisters all over my hands from the checkering on the grips.I was wondering if a flat top piston will make it even more difficult?I hate the iron sites on this thing so I plan on picking up a steel breech and a decent scope.Also I plan on turning it into a carbine so anyone have any scope suggestions?The main question is how to I get this up maybe 12-15fpe?What are the best mods to start off with to do so?I already know what I want to do for the externals.
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I built a 1377 with a Mellon flat top piston, steel breech,2289 foregrip,skeleton stock and 24 inch barrel.Its been awhile since I built it but I think it was shooting in the 700's.I put a lot of time Into it.The best shot I made with it was a hosp at about 45 to 50 yards.It was a nice shooting gun.
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12-15 fpe is not realistic. Pumping will get a little easier as the gun breaks in.
Since you are feeling the bruising common when pumping this kind of pistol, you might consider finding some semi-custom grips for it. It will be loads more comfortable to pump and hold.
Aftermarket aluminum breech would be useful for mounting optics or upgraded open sights, plus, it would be much lighter than a steel breech.
Flat top piston and valve should provide a bit of oomph.
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14-16 fpe can be done but it would not be with a 1322 pump tube but it would a lot look like a 13xx carbine
It would take a 664 pump tube, or a 2100 pump tube with a modded valve.
my 1322 with a 14.5 barrel is getting ~13.5 fpe so to me it is very realistic... It does take 22 pumps but I am still using a pump cup.
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as for scopes I like the tasco 3-7x20 it is nice and light and does not make the carbine feel unbalanced.
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Would 10 fpe be more realistic?And yea that is the scope I was looking at.Does the ftp make it harder to pump?
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Found this thread interesting http://www.crosman-air-pistol-owners-forum.com/board/index.php?topic=4935.0 (http://www.crosman-air-pistol-owners-forum.com/board/index.php?topic=4935.0)
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You should be able to reach 12fpe without getting too exotic but it will be more realistic if you use a longer barrel. My .177 is producing 10.7fpe with a 24" barrel on 14 pumps (or 10fpe on 10 pumps if I'm looking for a better return on my sweat equity). Another 1.3fpe is probably a given in .22 cal since it tends to be more efficient.
The changes that would bring it up to this level are:
1. shim the pump cup and stuff the piston (or get an aftermarket flat-top piston and valve)
2. replace the transfer port with a piece of poly tubing
3. install a longer barrel: something in the 18" - 24" range
If you're looking to do it on a budget then I have even better news. Other than a couple of dollars in hardware, the only thing you'll need to buy is the barrel which is only about $20 shipped direct from Crosman. A how-to guide I made a while back is linked in my signature below.
Do bear in mind that energy isn't everything, though. Accuracy is far more important considering your namesake. Hitting a marble-sized squirrel brain at 30+ yards with a .22 cal carbine producing 12fpe not trivial due to the loopy trajectory. This power level is much more suited to .177 cal because of the flatter trajectory. I hunt a lot and that is precisely why I converted mine from .22 to .177.
For example, a 14.3gr 0.22 cal pellet at 12fpe drops 1.2in between 35 and 40 yards. An 8.4gr .177 cal pellet at 10.5fpe (1.5fpe less) drops only 0.7in. How good are you at distinguishing the difference in 35 and 40 yards in potentially unfamiliar terrain? I don't mind admitting I have a hard time with it.
With that said, if you are keeping your hunting range inside of 25 yards or use a rangefinder religiously, the trajectory difference is not as important.
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I would listen to these 2 guys if I were you,
They have been around the block a time or 2 with the 13xx series of guns...
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You should be able to reach 12fpe without getting too exotic but it will be more realistic if you use a longer barrel. My .177 is producing 10.7fpe with a 24" barrel on 14 pumps (or 10fpe on 10 pumps if I'm looking for a better return on my sweat equity). Another 1.3fpe is probably a given in .22 cal since it tends to be more efficient.
The changes that would bring it up to this level are:
1. shim the pump cup and stuff the piston (or get an aftermarket flat-top piston and valve)
2. replace the transfer port with a piece of poly tubing
3. install a longer barrel: something in the 18" - 24" range
If you're looking to do it on a budget then I have even better news. Other than a couple of dollars in hardware, the only thing you'll need to buy is the barrel which is only about $20 shipped direct from Crosman. A how-to guide I made a while back is linked in my signature below.
Do bear in mind that energy isn't everything, though. Accuracy is far more important considering your namesake. Hitting a marble-sized squirrel brain at 30+ yards with a .22 cal carbine producing 12fpe not trivial due to the loopy trajectory. This power level is much more suited to .177 cal because of the flatter trajectory. I hunt a lot and that is precisely why I converted mine from .22 to .177.
For example, a 14.3gr 0.22 cal pellet at 12fpe drops 1.2in between 35 and 40 yards. An 8.4gr .177 cal pellet at 10.5fpe (1.5fpe less) drops only 0.7in. How good are you at distinguishing the difference in 35 and 40 yards in potentially unfamiliar terrain? I don't mind admitting I have a hard time with it.
With that said, if you are keeping your hunting range inside of 25 yards or use a rangefinder religiously, the trajectory difference is not as important.
I've been experiencing the above with my 18" barrel 2289 shooting farther than 35 yards and varying the distance. Made one of those clip board target boxes / pellet traps using duct seal. These are great because you can easily change where you're target is located and check your drop using the shoot-n-c type splatter targets.
You're only hope is to practice various distance shots and throw a lot of lead downrange to get a feel for where the gun is going to shoot at various distances. The drop is also impacted by the weight and shape of the pellet and lighter weight dome type JSB have worked best for me in that regard. Trouble is wind will effect your shot more with lighter pellets too so there's that to consider, especially over longer distances.
I have resolved to using RWS H-Point and shooting closer ranges with this gun to maximize their effect on prey target and accuracy. For now, that would be chipmunks but I think a raccoon is on my list soon so I'm going to sight it for some heavier hunting pellets and see.
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I like what this guy did http://www.gatewaytoairguns.org/GTA/index.php?topic=22203.20. (http://www.gatewaytoairguns.org/GTA/index.php?topic=22203.20.)
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I'm also close to 14 FPE with my 1322 using a FT piston and valve with a 14.5" barrel. This is my first 1322 but I'm not new to tuning airguns. They are fun to tinker with. My next one is going to have an 18" barrel and I'm hoping for 16 FPE.
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I'm also close to 14 FPE with my 1322 using a FT piston and valve with a 14.5" barrel. This is my first 1322 but I'm not new to tuning airguns. They are fun to tinker with. My next one is going to have an 18" barrel and I'm hoping for 16 FPE.
What other mods did you do to it?Also what numbers is is getting to produce that kind of fpe?
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What other mods did you do to it? Also what numbers is is getting to produce that kind of fpe?
Heavier hammer spring, lighter valve spring, extended bolt probe, bored and polished valve port to .160" bored barrel port to .160", poly tube transfer port, polished hammer. These are all quick and easy mods, some for accuracy but most for more velocity. It is shooting CPHP 14.3 grain pellets 660 FPS at 22 pumps.
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What other mods did you do to it? Also what numbers is is getting to produce that kind of fpe?
Heavier hammer spring, lighter valve spring, extended bolt probe, bored and polished valve port to .160" bored barrel port to .160", poly tube transfer port, polished hammer. These are all quick and easy mods, some for accuracy but most for more velocity. It is shooting CPHP 14.3 grain pellets 660 FPS at 22 pumps.
Yep - done all that to my 2289 and it's all helpful.
I did however over-polish a hammer weight so be careful. Remove too much material and you might have a problem with the bolt hanging up when you go to cock the gun because the pin in the top of the hammer will get too sloppy and can bind in the tube slot on you. I replaced with a stock weight and it's fine now.
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with a 2100/2200 pump tube well about 18-20 fpe( flat topped) seems pretty doable in about 18-20-22 pumps depending on how you build it...
My not to attentive mods hit the 17 fpe mark as a .25. I think as a .22 It would have been up on fpe (not enough valve volume for .25)
I hit ~15 fpe with the 664/66pump(still some tuning to do), there is more if flat topped I think 17fpe or so
my .177s are 13xx/ 760 stroke length and valve and are shooting about 750 fps with 7.4g pellets
all of these are overpumping a bit and enlarged valves on my part. 22 pumps is about as stressful as 16-17 pumps stock. point is when you
build each way has its stresses that means an aluminum barrel band or/and pump tube reinforcement if you are really buildng psi.
that is why I think mine are just about as far as I would go with the stock barrel band.
Most of the time I just use 10 pumps at 20 yards, 12 at 25 and 14 at 30...
here is a way of , getting with 7.9g pellets, 870 fps at 16 pumps and 786 at ten, a flat topped 766, it has a 20-20.5 inch barrel I think,
point is strap a 13xx trigger group and breach and sundries on that pump assemly and it will still kick some arse...
with each you will have to build for and watch durability...
http://www.gatewaytoairguns.org/GTA/index.php?topic=54854.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=54854.0)