Breaking 120 FPE with cast 25 acp bullets
Well I tried a different fire control system in the Condor.
I had been going stock hammer and weight and spring with the RL valve stem and Condor top hat set to .1.
I suspected my spring was a little tired, I have had it for 2 years and countless thousands of shots, not to mention leaving it cocked overnight on several occasions..
Marvin was using a stiffer spring, and I had some around made of the same wire, Airarcher springs, so I went to work on the old gal this morning.
First I opened up the inside of the Airarcher spring to allow the PW to fit inside, the wire being .80 as opposed to .62 would not allow it to snap in.
Then I shortened the spring to 3.5 inches, then reset the end flat.
Next I drained all the air out of my tank and tested to make sure I was not bottoming out on the RLAirguns valve stem with it set further out. I found that at .13 top hat setting, I still had a fully spring supported valve stem.
I put it all together and started shooting over the box. Before I was averaging around 930 FPS for 100 FPE with 2800 PSI which was the mazimum PSI that I could open the valve. I gradually increased my fill to 3200 PSI, if my gauge is correct and I suspect it to read a little low, and at that PSI I hit 1013 5 yards from the muzzle.
Two things changed at that level.
My trigger which was below 1 lb, started self discharging, I am glad I have good gun handling habits and had it pointed in a safe direction. So I set it around 3 lbs for now and will play with it later.
Accuracy improved. Marvin had said when he picked up the velocity, his improved, it seems mine does also. Shooting off the top of the 58 Mercerdes in the garage without a bag, just resting on my hands on the metal of the car roof, I shot a 10 shot group that was 1 inch vetically and 3/4 inch horizontally.
Adjusting that velocity back to the muzzle gave me 1024 FPS with the 52 grain bullet and that folks according to Hand loads .com is 121 FPE.
In the field where it counts, that means with a 70 yard zero, the bullet never rises above 1.1 inches to 70 yards, and gets to 85 yards before it approaches 2 inches of drop.
Comparing it to the 25 acp, you get to the actual muzzle velocity of the pistol round at 245 yards.
I suspect once I get the sizer dies, so that less pressure is wasted sizing down that slug in the lead and bore when the air hit it, I will see both an accuracy improvement and a veloctiy improvement.
Regards,
Roachcreek
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The repairs I made to day, I just drilles and tapped holes on the otherside of the frame for 10-32. Then drilled the holes in the bushing larger so the threaded screw would fit in.
I did both the front and rear bushing, I figured that eventually the other one would strip out.
Regards,
Roachcreek
they always do…
think u gotta be the only one who stripped more metal from their frame than me… 😯
I just bought them at Ace Hardware.
The repairs I made to day, I just drilles and tapped holes on the otherside of the frame for 10-32. Then drilled the holes in the bushing larger so the threaded screw would fit in.
I did both the front and rear bushing, I figured that eventually the other one would strip out.
Regards,
Roachcreek
However I spent the last few hours fixing another stripped frame bushing screw, one of the 1/4-24 repair screw I had put in before.
Ugh.
Roachcreek
that idea saved my ass, but i actually got 5/16 screws turned down for the bottom holes now. fine by me though, i got trouble finding 1/4-24 in stainless, if you got a source for em, please clue me in… 😕
It does shoot a little better, so I guess my hillbilly gunsmithing did not fuck it up too bad.
However I spent the last few hours fixing another stripped frame bushing screw, one of the 1/4-24 repair screw I had put in before.
Ugh.
Roachcreek
Regards,
Roachcreek
Nah,.,, really??? A dremel tool inside your barrel?
Don’t cut that choke off unless its your last resort. I was lucky to get a great result from that.
I probably did it wrong, I polished the lead with my dremel stopping often to fit one of my cast bullets into the lead.
I figured it was an experiment, I can always have the breech end recut by one of our members here who has a lathe. Cutting off the choke is another matter, but I may also try that.
I get tighter 5 shot groups, but alas I still get those flyers, just not as many now tho it seems.
I called Lee Prescision ,they are still two weeks out on my die.
Regards,
Roachcreek
Well, someone can, and those folks are airgunsmiths. Tony knows what to do as do DAQ and Barnes and most any gunsmith actually.
For a barrel in hand, you’d want to have a piloted reamer that will cut the proper profile and depth/length. The proper profile might vary with ammo and the depth will probably be pretty consistent. How long to make the lede will vary with the expected weight of ammo.
Sorry to you smiths if I confused nomenclature or jargon for the dimensions!
Can someone detail the tools and technique to cut a proper lede for a 25 caliber Condor ?
Actually, cutting a lede would put you in line with every PB that isn’t a muzzle loader and every custom gun or barrel maker. Only Airforce guns make you use your thumb to seat a bullet in the rifleing.
True, there’s rarely a need to go absolute perfect or oversize with an airgun bullet, but that’s not the question here. Even a slug that’s .0005 under groove diameter needs thumb pressure to engrave it into the barrel unless a proper lede is cut. Good ledes can make a huge impact on accuracy….as well as relieve thumbitiis!
Charlie I have always re worked the bullet to the barrel not the other way around . Stop and think why the barrel is made as it is . Barrel makers do not go through what they do for the fun of it . If you get the size of the bullet down right it will work . You know how much the barrel is tapered and you know the groove diameter . Use your head not a saw . Quite worrying about a little leakage through the groove and stopping it with a over sized bullet . Do the math . Does .0005-.001 under groove fit in the middle of the groove and tapper diameters . That should stop the shearing that the tapper is causing if that is the problem . Remember that the bullet has to pass over the lands while in the barrel . The lead has to be compressed or moved back to do so . It will take the route of least resistance . Which is first out ward with the right bhn of lead then rear ward . When it is pressed out ward it fills the grooves and helps seal the groove area . Marvin
My groups are much better and more consistant, some are just one wide ragged hole, but I still get flyers well outside the groups. So sizing is next, then if that does not do it, I will have someone here with a lathe lob the choke off, and then redo the breech lead section with a sized slug as a guide so it is exact.
Also my top hat has a tendacy to come loose, I have lock tighted it to the stem and the set screw are lock tighted, but when the flyers start cropping up regularly, 9 times out of 10 that top hat is loose.
Regards,
Roachcreek
lol! man you might be on to something! If sizing doesn’t help with accuracy may I suggest the lobbing off of the choke.
Benneboy,
They are two shot groups at 8 feet. 😆
Naw, 36 yards, 5 shot groups.
Roachcreek
nice rc! what distance was your group done at?
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Yeah they do strip out, and the last remaining 1/4-24 screw stripped out today, so it was a good idea to drill that second hole.
Success.
One of the things you have to do when you make a mod is to go back and try all the stuff you did before.
Being as I had changed the lead in the barrel by opening it up to accept the slugs with normal finger pressure, I had to repeat everything again.
I went back to the 95 to 100 FPE set up which is the Condor spring,hammer weight and hammer and RLAirguns valve stem and the Top hat at .12.
I cleaned everthing, the 1000+ FPS level had resulted in leading with the Breakfree lubing. So I lubed with a light coating of Moly like Marvin had suggested.
It took about 10 shots to get the barrels shooting again, but the results were phenomenal.
I was getting 3/4 inch goups for four or 5 and then a flyer to an inch and a half. Now I get a one hole cluster of 4 and a typical flyer that takes it out to just over 1/2 inch
I wish I was grouping this way with the 120 FPE, however I certainly can live with this performance at 100FPE.
Although I am still waiting for the bullet sizing die from Lee Prescision, I would call this 25 cast bullet project a sucess.
Polishing the lead seems to be the finishing touch, altough Marvin is probably correct in that it could have been solved with the sizing die.
One other thing to try is to get a new factory spring and see if the slight FPE improvement still shoots as well.
And I have to get myself a new frame one of these days, I have taken that barrel out of the frame hundreds and hundreds of times, or I can still drill and tap the top strap, or move the bushings on the barrel and drill and tap more holes.
Regards,
Roachcreek