MarauderAirRifle.com

[RidgeRunner05]

Got a chance to do a little more testing with the springs and HS slugs today. With the 22# spring cut to the same length as the 12.5# spring from war I was able to get 16 shots from a 3200psi fill down to 2600psi. There is more than likely another 8 shots to be had, but at an increase of the fill pressure. Here is the string:
H.S.- max preload
H.T.-4cw
49gr HS

(3200) 865,867,869,866
(~3000) 869,871,870,873
(~2800) 874,871,870,872
(~2600) 868,869,867,863

I am super stoked with this string. 16 shots just inside 1% making ~80ft/lbs with my bottle rod. After I got this string, I mounted my scope and proceeded to sight in at 50yds. I wish the accuracy was a little better, but at this power I think it's acceptable at 1-1.25" @50yds. I do need to check the barrel for leading as the slugs are tight to chamber. I'll do a thorough cleaning on the barrel and re test accuracy soon.

[AwesomeAnt]

Nice work Ridge. With 80fpe close counts, Bullfrog showed how a 70fpe shot that was a little off was DRT. That's part of the perks of having that kind of power.

[RidgeRunner05]

So a little bad news on the pistol springs. After cleaning my barrel(which was filthy lol) I was planning on testing for accuracy with the slugs yesterday afternoon. I topped off the rifle to 3200psi to re check the string I had shot before with the 22# spring and the velocity had dropped over a hundred feet per second. I checked the H.S. and H.T. adjustments and they were still where they had been set for the string. Broke down the gun and checked my o rings, breech seal, and tp seal. All good there. Refilled the gun and same thing.... I think having the spring at max preload caused it to "set" and caused the loss of velocity.

I did swap back in the 12.5# spring from WAR, and worked up a tune for the 49gr slugs with it, though.
H.S.- 5cw
H.T.- 3CW
3100psi to 2500psi
805-821-800 for 24 shots
~70 FPE
After getting this string with the WAR spring, I think that cutting down the pistol springs changed the rate of the springs. This is close to what I got with the cut down 18.5# pistol spring.

The gun is back to "backyard friendly" with the 12.5# spring now(it had gotten loud with the other springs) After cleaning the barrel the groups shrunk to 1/2-3/4" @ 50yds. As for the power, they blow through a pine 1"x6" board like it isn't even there at 50 yards. Gonna have to upgrade my backstop to shoot these things lol.

I do want to try the 17.5# spring from mcmaster/Carr with the slugs to get the FPE back up for coyotes and hogs.

[Shorty]

Ridgerunner,
I messed around with making a couple hammer springs. I have some data here with designs and compression force ( http://www.gatewaytoairguns.org/GTA/ind ... ic=77968.0 )

My data shows that springs that have 0 or negative pre-load always increase shot count. I have also made a dual wire spring that seems to out perform the single wire springs in regards to maximum FPS or FPE with highest shot count vs long single wire springs with twice the amount of pre-load.

I am not selling the springs, it was just for fun and learning. Although, I have passed a few out. If you want to try one out with your WAR equiped 25 I'll send one out to you. I am sending another one out to Bullfrog so he can test it out too. So it would be a good comparison if you want to try it out.

[AwesomeAnt]

Nice to see your groups shrink that's Awesome. I use 12x12s as backstops, then 2 sheets 7/8 ply with 1/4" steel plate in between the plywood. An AK round will go through 8x8s. AR 15 won't go through 8x8s with standard ammo.

[Bob La Londe]

My data shows that springs that have 0 or negative pre-load always increase shot count. I have also made a dual wire spring that seems to out perform the single wire springs in regards to maximum FPS or FPE with highest shot count vs long single wire springs with twice the amount of pre-load.

I had never thought about that, but it makes sense. With zero preload its not as likely to double tap the valve. All the stock and aftermarket springs I have seen for the Marauder had some preload as you have to push the rear retainer in against the spring to set the screw in the trigger mechanism that holds it in.

I just put a 10 lb spring in my .25. I'll see what it does at 0T 0P 6 V. I'm not doing much testing for a few days. I am waiting on a new carry bottle to come in. I'm not filling direct because the 3000 PSI female Parker coupler on my pressure manifold has started shedding particles. I decided I didn't want to be anywhere near it so I didn't even toss it in the trash. I carried it directly out to the dumpster.