1720 T hammer throw

[Struckat]

Please school me on hammer throw.

When I bought it used in 2022, I installed a Prod TP in it to bump the power up a little.
At that time I found the hammer throw screwed most of the way in, shortening the throw.
I backed off to what my Prod looked like and have been shooting it that way ever since.

It’s shooting right where I want it 690ish with 9.3 Supermags with very good accuracy. Maybe not its favorite pellet, but still very accurate for chipper and hosps.

I am not asking where it should be but rather what reaction should I expect or look for as I adjust it. Maybe flatten my curve a little?

It is such a sweet little rifle. The bipod is only for bench shooting. In the field a sling mount is attached. It weighs half as much as my HW30.

I still can’t figure how to post photos here right side up. This only happens here for me.

[Frank in Fairfield]

If you turn the HT fully CCW, it will increase the throw and increase the speed (Inertia, you know?).
If you turn the HS CW it will also increase the speed (more spring force).

[Nukall856]

Struckat,
 
 It sounds like you are asking about tuning your 1720 by adjusting the hammer spring tension. Turning the adjustment out or CCW will lower the spring tension and increase the hammer throw and will result in a lower powered strike from the hammer. Turning the hammer spring adjustment in or CW will increase spring tension while shortening the hammer throw resulting in a harder strike from the hammer.

  To find the right setting that you want You will need to start by gathering a shot string through your chronograph. Start from the fill pressure you normally start from and shoot it down to where you normally would stop. I like to get non regulated PCPs to shoot within 30 FPS from beginning to end with the peak power near the center or middle of the shot string.
 If the power is low in the beginning and the power kicks up near the end, then you need to add in or CW adjustment. If your shots start and begin to decline in velocity after a few shots and ends with a much lower velocity than the start, then you need to adjust out or CCW.
 Keep testing till you find a setting that starts low in FPS gets to a peak and falls back to the beginning FPS. I setup to have 20-25 shots with in 30 FPS in alot of the different non regulated PCPs I have.
 Based on the shot string you will need to find a start setting to stay within the 30FPS.
  Hope I made it clear enough. Good luck Struckat

NVak

[Struckat]

Thanks Nukall, but I was asking about the throw, not the spring.

Shortening the throw gives the hammer less distance to move before it hit the valve.

I will play with it some and see what happens.

[Nukall856]

Yes the throw adjustment does change the spring setting. Let us know how it goes. I don't know much on the 1720 so it will be an interesting read from you.
 
NVak

[Mzq284]

Dang, that IS a super sweet rifle! I hope you get it sorted out. I see you're running an older crosman elm stock, those have some really nice grain. I'm tossing around idea of doing the same with a PRod in the future, you're not helping!

[Struckat]

Oh it is shooting just fine. Nothing to sort out.

I was only asking what varying the hammer throw does.

The elm stocks are beautiful. Sand them lightly and the have a texture that like the feel of.

Why would they have put the finish on them and cover the grain I don’t know.

[Van]

Oh it is shooting just fine. Nothing to sort out.

I was only asking what varying the hammer throw does.

The elm stocks are beautiful. Sand them lightly and the have a texture that like the feel of.

Why would they have put the finish on them and cover the grain I don’t know.

   I could not understand why they put such a dark finish on most of them either.  I get my Elm stocks from Numrich and use stripper first then wash with a solvent.  After lite sanding and honey maple stain, they look like my old Sears Elm wood guns that were not stained so dark. Numrich still has some used Crosman 160 stocks listed for $29. The Disco type trigger packs I use have to have some inletting done in that area to work.  I glue a wood dowel in the original action mount hole and drill it for the new mount bolt. The Disco/2260 type trigger pack mounts a bit forward in the stock more than a 160.   I glue a spacer at the back of the trigger inlet and redrill with a forstner bit for the new trigger. They also look great finished natural.  Some have asked if they are they are laminated but it is just the way the grain is cut.  Here is one I finished recently.   

[Mzq284]

They can be beautiful. My 362: