Beeman P1 Pellets .. recommendations for target shooting.

The P1/hw45s are industrial works of art. Mine shoots best with the JSB RS 7.3s. 



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I have a HW45 which is the same thing as a P1. My best results are with JSB 8.4's. At 10 meters I can usually shoot 10 shots into 1 1/2" standing, and occasionally I'll get it down to an inch. I'm not sure if that is good but it is a fun gun to shoot. 

My best results are with a firm 2 handed grip, but not tight. It's loose enough that the gun actually jumps forward a little bit on firing. It does that because unlike most spring guns the piston actually move toward the back not forward. If you want to "bench rest" it for some accuracy testing, support your forearms on a rest, focus on the front sight and learn the break point on your trigger.

Looking at your picture, since the chunk came off the top it could be from a pellet or pellets that were not seated. It's for that very reason I don't use Crossman pellets. They don't seat well in most of my guns. The JSB's seat flush with just medium finger pressure and it's a much cleaner pellet. 

Your breech looks thinner from 12 to 2:30 area. If it's not concentric, lining up with the transfer port, or badly machined channel for your seal, could be the problem.

A breech seal should seat so you just feel it with your fingernail. If a tissue or piece of Teflon tape blow off when you fire, you don't have a good seal. Could be the breech seal or combination of tolerance stacking that just blows it out everytime.

If it's under warranty, I'd be sending it back for another. If warranty ran out, you can try & size one yourself or get a smith/machinist/tuner to fix it.

I learned that breech seal fit & consistent pellet seating depth are more important than I thought, and measuring in the thousandths to be optimized. Just as important as a perfectly sized pellet can show a huge difference as opposed to an ok fit. When all these and more aren't perfect, that's tolerance stacking, and you end up with a poopty shooter & the human eye can't usually pick out the problem.

If you try another factory sized seal & have same problem, I'd utilize the warranty.

As far as best pellet. Get a sampler, and I'd try every H&N FTS/T in every size the have 4.50,4.51,4.52,4.53,4.54,4.55 and once your breech seal is fixed, see what size shoots best and compare over Chronograph.

You could just buy 4.54 or 4.55, push one through and measure with micrometer. Then buy that size & start sorting with a Pellet Gage, mic, scale, rolling. 

Or just shoot any weight JSB you want and see what works but you won't have great consistency until the breech seal is fixed.

 When the top part of the gun is closed, the barrel rotates down and is locked in place with the breech end resting on and compressing that seal. The barrel, as you know, is only about 3/8" in diameter. If the barrel is not centered and completely square to the seal the unsupported area will likely cause the seal to bulge. 

The barrel is held in place at the breech in a "U" shaped block which has a small strap with 2 screws to secure the barrel. If those are loose or were removed for some reason and not put back with the barrel properly centered, that may be your problem.

Here are 2 things you can try to see if the above is an issue:

First: Look in from the side of the gun as you close it. The barrel should have some degree of contact on the seal before it snaps closed. On mine, when I tried this I could tell when the barrel finally closed it did put a fair amount of compression on the seal. With the final bit of closing that takes place, which you cannot see, it's easy to guess the squareness of the angle.

Second. MAKE SURE YOUR GUN IS EMPTY. TRY THIS WITH A MIRROR IF YOU DON'T WANT TO LOOK DOWN THE BARREL. With the gun closed, shine a light down the barrel and position your eye so you can see the transfer port. (It's the hole that the breech seal surrounds.) It should be in the center, not off to one side. If it is off to one side that means your barrel is not going to make complete contact on the seal.

The fix is to center the barrel by shimming the "U" shaped block to get your barrel in proper position. If your not sure on how to do this it would be better to send that fine gun in to someone who could get it back in action.