Likin it so far…….Brocock Compatto .22

Forums PCP Airguns Likin it so far…….Brocock Compatto .22

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    hawkeye69
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    “DrPutz”Yes, I believe I got the crown idea from your other post about Kip fixing the problem.  It has worked very well so far, but with the cold weather I have not been able to stretch out the shooting distances yet.

    
I had inconsistent results after Kip worked on it using 18.13 JSBs. I was thinking about replacing the barrel,  but when I switched to 15.89 JSBs it’s pellet stacking at 30 yards. Just to add, I didn’t expect to have that kind of issue with a new gun in this price range. Seems like it isn’t an isolated problem and definately something that quality control should catch at the factory level.

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    Element
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    Was the crowning done in house at AOA or sent off, wondering if a guy could do it themselves as some of the videos show online?

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    hawkeye69
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    In house while I waited. Didn’t take too long, 30 minutes or so
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    Element
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    I think I have made some headway with my older compatto, measured the stock spring which is 2.5″ cut it down to shy of 2″ there is little to no tension on the hammer! I shot some pellets through her and she has good velocity, no chrony readings yet, sounds like it should, not wasting a bunch of air like before! My question is I wonder what is up with the hammer spring and the length of it? The spring had a plastic sleeve over it about a 3/8″ tall but was split, broke if you will on 1 side, not sure if that would of been a player in all this? Thank you guy’s for input on this!  Steve

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    BigTinBoat
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    Steve,
    That sleeve is supposed to be there. I think it kinda keeps the spring off the tube and centered. Good to see that you are making progress. I think you will find that the velocity has dropped a bit. Like Dr says, turn your set screw in hammer in till it’s flush, this will get you max throw. Once you chrony, if you find the velocity is low let me know. My springs are coming in tomorrow. I got 10 so I will send you one of each if you want.

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    Element
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    Bigtinboat that sounds great, I did leave the hammer screw out about a 1/16″ or close to that, I’ll back it flush with the hammer face, I’ll reinstall that sleeve then! Maybe get some chrony time tomorrow, I actually shot a couple magazines full without much pressure drop I’m so pumped this was my first pcp so glad I can bring her back! The spring length still has me puzzled!!!

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    DrPutz
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    The split plastic tube is a “depinger” that the factory adds.  With a short, strong spring, you really don’t need it.  As for my crowning – I am using a simple countersink bit, then cleaning up with a rubber wheel and finally polishing with Mothers Mag Wheel polish.  I get quite a bit of dirt/grit in the barrel, so I put in a pellet to avoid getting grit down the barrel and I replace the o-ring afterwards (hence my discovery with viton). 

    Tonight in my 177 testing with a regulator, I was getting 40 shots, 3% variance 1.0 fpe/ci over 190 to 115 bar (reg is set at 140 BAR) at 17 fpe.  The last 10 velocities were’nt great, so I should probably stop earlier.   I need to make air this weekend, hence the low starting pressure.  I usually fill to 220 bar – I should only have to fill once per FT Match with this setup.  Next up is to re-tune the 22 for silhouette.

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    BigTinBoat
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    Doc,

    Looks like yo have just a bit too much hammer. Looks like you came off the reg at shot 30 and went straight down. I think this also effecting your variance in shot speeds. If you stop the string at 30 and use 140bar your efficiency is almost 1.2fpe/cuin. ack off spring a bit and I think those little peaks will go away.

    Also I think I would call the plastic sleeve a “De-Boinger”. It stops the spring from hitting the tube and cause the “boing” to transmit thru it. There is no way it would effect the air movement inside the tube (the ping) after the shot.

    I was worried about my barrel so removed it and noticed no “rough” spots at all. I did use a grey “rubber” dremel bit to polish it followed by MMP on the cone cloth dremel bit to make it like a mirror. I removed the breech oring and then put a Q-tip in the barrel to stop any grit from going down it. Not sure but mine might have been “crowned” before as it looks to be no way for a pellet to hit the edge of the barrel as the edge is larger then the exit hole of the mag and tapers inward. The end edge is covered by the mag plate itself.

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    Element
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    Did a little chrony wrk with the compatto shooting around 720fps with some 14grn crossman pellets, ended up adjusting the hammer screw outward more about 3 turns and also shimming the hammer spring about an 1/8″ ended up with 780 fps! As a comparison I shot the Bantam she registers around 870 fps same weight pellet! Gonna need to try some of the different springs! Thanks everyone for the input!  Steve

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    DrPutz
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    BigTinBoat – thank you for the suggestion of the hammer spring.  I had upped to the next larger hammer spring when I had problems with the Viton o-rings, I will have to drop back down and test again.  I need to cut a bit off the lighter spring to reduce the bounce and make some air this weekend.  One thing on the 177 is the regulator (huma old school) takes up a bunch of space for extra plenum, so probably working with only 126 cc’s of air.

    For the breech crown, you may need more than you think.  My original was about 1/16″ – I upped that to about 1/8″ since it would not harm anything.  On my 25, the JSBs feed much easier now. 

    Here is a shot string from tonight from the 25 cal with Barracuda pellets – 220 to 120 bar, 1.4 fpe/ci efficiency 5% variation for 40 shots.  Probably a bit too far on the number of shots, but could go to 230 bar, once I have more air.  The 25 does JSB 25.4 gr (old style), Barracuda Extreme, and Barracuda Hunters all at 30fpe.  The Barracuda’s are the most accurate at the moment at 50 yds.  I’m not sure the 25 cal is living up to the extra expense of the pellets – may have to get a 22 Bantam instead.

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    DrPutz
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    Element – the problem with cutting off the factory spring is that it is too light to be un/less-loaded.  You have to increase the spring wire diameter to somewhere around 0.057″.  The factory has the original spring is preloaded quite a bit, which creates poor efficiency despite the slingshot hammer.  Once you go to a stronger spring and “negative” preload, you will be impressed at the extra speed and efficiency.  The trade off is a bit more cocking force.

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    BigTinBoat
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    “Element”Did a little chrony wrk with the compatto shooting around 720fps with some 14grn crossman pellets, ended up adjusting the hammer screw outward more about 3 turns and also shimming the hammer spring about an 1/8″ ended up with 780 fps! As a comparison I shot the Bantam she registers around 870 fps same weight pellet! Gonna need to try some of the different springs! Thanks everyone for the input!  Steve
     

    
Steve,

    My springs came in. PM me your address and I’ll send you one of each.

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    BigTinBoat
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    “DrPutz”BigTinBoat – thank you for the suggestion of the hammer spring.  I had upped to the next larger hammer spring when I had problems with the Viton o-rings, I will have to drop back down and test again.  I need to cut a bit off the lighter spring to reduce the bounce and make some air this weekend.  One thing on the 177 is the regulator (huma old school) takes up a bunch of space for extra plenum, so probably working with only 126 cc’s of air.
    For the breech crown, you may need more than you think.  My original was about 1/16″ – I upped that to about 1/8″ since it would not harm anything.  On my 25, the JSBs feed much easier now. 
    Here is a shot string from tonight from the 25 cal with Barracuda pellets – 220 to 120 bar, 1.4 fpe/ci efficiency 5% variation for 40 shots.  Probably a bit too far on the number of shots, but could go to 230 bar, once I have more air.  The 25 does JSB 25.4 gr (old style), Barracuda Extreme, and Barracuda Hunters all at 30fpe.  The Barracuda’s are the most accurate at the moment at 50 yds.  I’m not sure the 25 cal is living up to the extra expense of the pellets – may have to get a 22 Bantam instead.

     

    
I honestly didn’t have any trouble feeding any of the pellets. All just a smooth as could be. With the H&N FTT (5.55head) There was a bit of resistance, but not as the pellet was entering the barrel, it was just prior to the bolt latching. I’m sure this was from the larger head size. I’ll keep an eye on the accuracy. It only takes 5mins to remove the shroud and barrel. Will get to cutting the springs and testing tomorrow.
     

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    DrPutz
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    One thing to look for is lead shavings below the magazine.  For the life of me, I could not figure out where they were coming from.  I disassembled the magazine and trimmed all of the sharp edges.  Then with hawkeye’s post it dawned on me that they were coming from the barrel edge.  Mystery solved – if you see these shavings you may have a problem (or stop using those crosman pellets ;).

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    BigTinBoat
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    “DrPutz”One thing to look for is lead shavings below the magazine.  For the life of me, I could not figure out where they were coming from.  I disassembled the magazine and trimmed all of the sharp edges.  Then with hawkeye’s post it dawned on me that they were coming from the barrel edge.  Mystery solved – if you see these shavings you may have a problem (or stop using those crosman pellets ;).
     

    
I’ll make not tomorrow when I’m tuning. I usually use the cheapo CPHP for that. I did just order some AA 16gr and some PolyMag 16gr to try for hunting.

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    DrPutz
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    DrPutz
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    Second try at the post – the forum is not liking me tonight…

    I had to post some great success tonight with the Compatto – finally warmed up and I could shoot outside.  I do bucket and sticks mostly – HFT style.  I was shooting at 50 and 55 yards with my regulated 177 in a bit of a breezy wind – my groups were mostly below 0.75″ for 5 shots at 50 yards.  I even had one 10-shot group at 0.8″.  Boy these Compatto’s can really shoot.  Ignoring speed, I was getting 60 shots from 220 to 120 bar just as the POI started to change.  I think that the speed is a bit high and can bump it down a slight – I saw one or two pellets spiral a bit.  The rest, I could drop into the 3/8″ circle with ease, sans the occasional breeze. 

     

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    DrPutz
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    Let’s see if I can get a picture now…

     

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    BigTinBoat
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    That’s fine shooting with a .177 at 55yds. I’m on the search to fine a .177 Bantam Hi-lite right now. If I can’t get one of those I’ll look to Compatto .177, but really likin the wood and CF bottle on the Hi-Lite.

    BTW – I think your posting issues has to do with the location you had your pics hosted. Those “data:image/png;base64,iVBO…” address’ are a few thousand characters long. Uploading the image to AGN is much simpler. When I get those email notifications and your pics are attached it freezes the email a couple time due to the address of the pic being as long as it is.

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    Element
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    Big thanks to BigTinBoat for sending me a couple of springs, starting the tune process with the compatto without the slingshot hammer was able to reach 800fps with some cheap 14 grain crosman pellets used for tuning! Will see how it goes if we could only get the weather to cooperate!  Steve 

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