First time poster and new to PCP

This area is dedicated to the .22 caliber Benjamin Marauder by Crosman.

Re: First time poster and new to PCP

Postby cptmclark on Wed Jan 19, 2011 4:42 pm

RANGE REPORT: Finally, not ideal conditions, but my only opportunity this week. I de-gassed the rifle using the tool, them pumped it up to 3000". There was one point at 2500# where it went backwards a bit, then resumed climbing at 10# per pump, exactly. So 300 pumps to fully charge it. Pump works, gun works. YAY! ----- Chronograph set up and lame bench is picnic table with standard fwd and rear bag. Distance 35 yards, cloudy and late in day, very light snow, no wind. Pellets were taken at random from a tin of "Premier Ultra Magnum hunting pellets". I could do a bit better with bright sun, solid bench, and more experience with the gun and trigger, but I have confidence that I held within my 1/4" aiming point, which was centered in a 0.9" circle. Heartbeat was greatest variable. The velocity dropped off with virtually every shot. Question: Is that the way it's supposed to work? I thought there was a regulator to keep velocity constant. ------- Starting at 3000#, chrono string for first ten shot group was: 873.5, 871.4, 869.9, 869.9, 869.4, 868.4, 867.9, 867.2, 864.1, 865.1. Average 868.7, ES 9.36, SD 2.64. There was one wild flyer 2 inches out, making the group measure 2.26". throw out the obvious flyer and you have a 9 shot group of 0.884" (about 2.5 MOA). -------[b]GROUP 2[/b]: 855.2, 853.1, 854.5, 850.4, 847.5, AVE 852.1 [b]Group size is 1.17". ENDING Pressure after 15 shots was 2400#, which I codgitate to be using 40# per shot. IS THAT NORMAL? -------
Third group, 5 shots; I lost the first three velocities, so xxx, xxx, xxx. 833.8, 832.2. Ending pressure was 2200#, and group measured 0.97", including an obvious flyer. Throwing out the flyer would give a four shot group of 0.425". Fourth group; 5 shots, 835.2, 823.6, 821.6, 812.3, 811.1. --Ending pressure was 2000", and group size was a very scattered 1.75", with velocity falling fast at the end. --------As is, present setup is giving average of about 1 inch groups at 35 yards. That's almost 3 MOA. ---If this is typical performance, is it a good guess to say I'm only getting about 20 shots within a reasonable velocity range? I hoped for 1000 fps (just subsonic) but would that reduce my shot count way below 20?-------I understand that testing many pellet types may shave group size, as may some other techniques. I have not lapped the bore nor dressed the crown. Do you gurus believe that I can reduce my group size by two thirds? That seems unlikely, but this is my very first try with this type of rifle, so I'm eager for opinions, facts, and advice. Sympathy not required but is OK.
cptmclark
 
Posts: 17
Joined: Tue Dec 21, 2010 8:19 am

Re: First time poster and new to PCP

Postby detox on Fri Jan 21, 2011 7:23 pm

Beeman Kodiak or H&N Baracuda Match 5.52mm pellets will shoot better. I also apply moly to the barrel to reduce lead fouling (takes a few shots for barrel to settle down afterwards). Some people use Krytech to lube their pellets to reduce lead fouling.

I recently changed my tune for better accuracy. I am still searching for consistancy.

Fill pressure 2000
Hammer Spring 2.25 cw
Striker 4.3 cw
Transfer Port 2.125 ccw

Here's latest target. http://i1225.photobucket.com/albums/ee3 ... target.jpg


...
detox
 
Posts: 33
Joined: Tue Dec 21, 2010 8:31 pm

Re: First time poster and new to PCP

Postby detox on Sat Jan 22, 2011 8:31 am

cptmclark,
Try shooting from sand bags. My Marauder shoots better using them.
Readhere:
http://www.network54.com/Forum/673067/m ... vise+and...

I would also loosen barrel shroud 1/2 turn from full tight away from receiver. This will make the barrel a true full floated barrel.









...
detox
 
Posts: 33
Joined: Tue Dec 21, 2010 8:31 pm

Re: First time poster and new to PCP

Postby cptmclark on Sat Jan 22, 2011 11:19 am

Thanks. I'll try those things. Not sure about the moly. I wonder if it works like teflon. I've used Remoil (with teflon) in my rifles for all purpose clp and find it takes a few shots to clear it out of the barrel, while accuracy is aweful. Maybe the same effect. So I quit using it for bore protection.

I do use sandbags, a conventional benchrest set up. Pellets are pricey to test, if I have to get 500 each. Of course, perfection isn't supposed to come easily :(
cptmclark
 
Posts: 17
Joined: Tue Dec 21, 2010 8:19 am

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