Simple 1322 Power Mod

Benjamin David | February 2, 2021
Crosman 1322 Piston before being bored out for a 7% increase in internal air volume.

Looking for a simple 1322 Power Mod? With a steel breech, the Crosman 1322 can be over pumped for more power. However, a larger air volume will increase the amount of energy the 1322 can store. Longer and better valves, like the Alchemy Airwerks valve, can achieve an increase in power, and can be purchased on eBay.

There is a crude DIY method to increase volume about 7%. It requires a 25/64 drill bit, a drill press, and a drill vise.

The original internal diameter of the valve cylinder is about 3/8″ or 24/64″, which equates to an internal volume of .39 cubic inches. Boring out the diameter to 25/64″ increases the internal volume to .42 cubic inches. Or a 7% increase.


Trying this DIY method of increasing the cylinder valve’s internal volume can ruin your cylinder valve. You can also hurt yourself if you aren’t careful. Its not something that should be tried without a drill vise, and drill press. Sportsman’s Magazine and its authors, are not responsible for damaged parts, or injuries that result from using the 1322 power mod mentioned.

Mod the Valve

Place the valve in the vise, and carefully align the valve with the drill bit, so that the drill bit is perfectly centered. Make sure the bit is securely chucked, and the cylinder valve is secure in the vise. Lubricate the bit and valve with a cutting oil, almost any lubricating oil will work.

Carefully advance the drill bit. Be absolutely sure the drill bit is not off-center. Frequently back the bit out, clear the aluminum shavings, add lubrication, and advance the bit.

Frequently check the depth, or measure and set a depth gauge if your drill press has one. Drilling too far will destroy the cylinder.

Crosman 1322 Cylinder

Crosman 1322 cylinder valve before being bored out for a 7% increase in internal air volume.

Boring a 1322 piston

Boring a 1322 cylinder valve on a drill press with a 25/64″ drill bit.

Bored Crosman 1322 Cylinder

Crosman 1322 cylinder valve after boring out material with a 25/64″ drill bit.

The Crosman 1322 is a favorite platform to modify and tinker with. Our simple 1322 Power Mod uses stock parts and some precision drilling, to achieve a 7% increase in air volume. It won’t make your Crosman 1322 twice as powerful, but its one small step in the right direction. Let us know what you think, or if you have any questions.

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Written By Benjamin David
Benjamin is an avid outdoorsman with a wide range of experience hunting, fishing, climbing, and backacking. He brings his knowledge and experience, to Sportsman's Magazine, and is a major content contributor. Leave Ben a comment or question.

2 responses to “Simple 1322 Power Mod”

  1. […] The easiest way to get more power out of a stock 1322, is to add a steel breech, and over pump it. The next step is to increase the air volume of the cylinder valve, and polish the internal faces of the air ports. You can buy a high performance one, or you can take a crack at modifying one yourself. Check out this DIY power mod article. […]

  2. Nobody Special says:

    Decent recommendations on the mods. There are a couple others that do a good job as well. For example, you can cut a good 1/8″ off of the threads on the front half of the valve for a decent increase in volume. you still want to be able to get at least a full turn of threads, if not a little more, but not too much more is required to safely hold pressure in the valve. Doing this will significantly increase the amount of air you can store, but it also means more pumping just to get up to the same pressure you were before modification. So, ten pumps after the mod will not pressurize the valve as much as ten pumps did before the modification, but you can pump a lot more air into it, and if you enlarged the transfer port, and beveled the exit port on the back of the valve, you’ll put a lot more air behind the pellet and faster, with a better likelihood of dumping all of the air. You can also give the internal valve spring a squeeze to soften it up, or even cut a coil off of it. Why do this? Softer spring means less resistance against the hammer, so it opens faster, and dumps more air faster. Mine is soft enough that if I don’t cock the hammer, it won’t fill, but once the hammer is cocked, it will hold air just fine. It only has to have enough tension to hold the petcocks in place for the first pump or two. After that, the air pressure will hold them in place just fine.

    You can also add a threaded barrel band from GMAC for threading on a silencer. I still have the stock barrel with a steel breech.

    • Benjamin David says:

      All good comments and good suggestions. Thanks for posting all of that. We published this as a single sort of decent power mod, without trying to go down the rabbit hole on customization. It seems like most people want a simple mod, or plug and play parts for performance…. and then there are the rest of us who will do what you’ve mentioned and more to squeeze out every last bit of performance.

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