Doing valve work in preparation for 52 grain bullets
I have RCBS 25 acp mold coming the first of the week, I also have some bullets coming from a TAG member from his RCBS mold. I have not mentioned his name, so he does not get besieged with requests for bullets if he wants to chime in he can.
He is sending me two different diamater bullets so once I find out what my rifle likes, I will order a custom sizer die from Lee Prescision.
The thought is that if the bullets don’t shoot in my gun, I will send the unused mold back.
I have been shooting a RLAirgun valve stem and Tophat turned all the way out to .0650 or so and the powerwheel maxed out.
With Kings I get 1065 FPS with a 2500 PSI fill, any more than that and it valve locks. If I load two kings in to see what the 51 grains does, I get 850 FPS.
The member sending me the bullets gets 918 FPS with a stronger spring, a AF hammer, no Condor weight and a 177 valve.
First I tried the RL stem, Airacher valve retainer and spring with a AF Tophat to get a tophat setting of .110 and the Condor hammer and weight and full powerwheel setting. Not much difference than what I had before for velocity.
Then I put in a 103 grain hammer I got from Subsonnic. I filled to 3000 PSI, velocity incresed to 1150FPS with Kings and 930FPS with two Kings. Eventually I set the tophat back to .85 and got 1162 with Kings and 945FPS with the double King 50.8 grain load. That should put those 25 ACP bullets right around 100 FPE.
Another combination I tried was the Airarcher barrel ferrel, spring, hammer, valve retainer and spring and RL valve/AF tophat set at .120 and spring and a 3200 to 3400 fill depending on which gauge I use, yes even the big gauges are eratic. I got 985 FPS with the double King load, I was still in the 1165 FPS with a King. This set up uses a lot of air for the added velocity, the shot string was very short, so I decided to go with the 945FPS/100 FPE comination to start with.
I shot some Kings at 25 yards with the 1162 FPS velocity, accuracy was about what I get at 80 yards with the 1065FPS velcocity which is around 3/4 of an inc.
It seems breaking the sound barrier with Kings makes accuracy go to hell, gosh whoduh thunk. 🙄
I will let you folks know how the 25 ACP bullets shoot when I get them the first of next week, hopefully they will fly straight enough to give me accuracy capable of shooting larger varmits.
BTW, the 25 ACP pistol round gets 750 FPS so this is a 200 FPS increase with an airgun.
Regards,
Roachcreek
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RC, I can attest to the fact that steel and aluminum go better together than aluminum and aluminum under load conditions!!!
I need to say something . I have not casted as long as many . But I have a very good teacher that has . And he never forgets a thing . He keeps me on track most of the time . I do cast with a harder lead than most most of the time . But that is largely due to having acquired over 3200 pounds of lead that I have maybe $75.00 invested in . Any were from 5 – 18 bhn . And in working with him and this lead I have learned a lot . This bullet I have only casted in the 12 bhn because it has worked and I have a lot of that lead . The bullet that needed that 12 bhn lead is the 30 grainer . And for what ever the reason that same bullet does not like 850 fps and slower . The faster it goes the better it groups up to 1200 fps so far . Marvin
I had a aluminum breech Subsonnic made for me, he had trouble with it binding, and eventually he covered it in a plastic sleeve. It was always a little difficult to operate, I sold it with a Airarcher I built up, for that it was great and for that a metal breech is best I think.
Perhaps a steel one that is scultured to reduce weight and highly polished would work to reduce the aluminum agaist aluminum galling thing.
About the cast .25 ACP bullets, if you have some one who will do it for you, your truely blessed. I have not found anyone who sells them other than the fine fellow furnishing me with a few to try.
If you buy one of these RCBS molds from Midway and furnish it to your caster you might create a source for yourself.
As far as sizing. If your caster will size them to the specs you need, your ahead, the other cheapest route is to buy a Lee press and have a Lee Prescision sizing die made to your specs, they list them at $35.00. A lyman 450 or RCBS sizer lubricator will run you around $175 new with dies once you get it to your location, the entire Lee set up is less than $60.00.
Lube is another matter, the Lee works best with lubed bullets prior to sizing, I now use Johnsons paste wax, but Breakfree or ATF works fine, it is just messy.
I have cast for a few decades, but I suspect Marvin has forgotten more than I ever knew and still remembers more than most casters would hope to. Marvin is always into getting the alloy the correct hardness, he casts at 12 BHN whch I think most would consider hard for airguns, but it is hard to argue with success.
I have cast for smokless rifles, pistols and shotgun slugs, Black Powder pistol and the large Black powder single shot cartridges, but the airgun thing is new to me. So far I have only cast the big 452 slug I have in that picture for airguns. My old Sharps Borschardt 1000 yard target rifle used to put the first 3 shots of 10 shot groups with 550 grain bullets at 200 yards into a cloverleaf before the Blackpowder fouling and my jitters would push them to around 3 inches.
That, and taking elk with my homemade bullets were the high water marks of my casting career.
Regards,
Roachcreek
I just stuck that in there to show what happened. I had the stock knob in there when it happened. Going to go a different route. I figured out why it did it.
Shot some more Surefires and they are still just under 2 MOA. It appears that 1 MOA or less is possible but it is going to take sized .25 ACP slugs sized right to do it.
I found out I can get a batch of 500 made up as a custom order by a local cast guy who makes casts for the Cowboy folks at our local range.
What’s the most cost effective way to size them for my barrel correctly? Slug the barrel like RC mentioned and have Lee created one? Have them sized to the values JVH is using? This is leaving my skillset. Guess I need to do a little reading.
Lee is pretty inexpensive.
http://leeprecision.com/xcart/Custom-Services.html#LSK
I blew one out day before yesterday shooting 7 rings with the Airarcher fire control setup. It was the rear screw on my Subsonnic bolt, but it had be loose for some time.
Regards,
Roachcreek
A shoulder bolt will help keep the twisting action tearing at the threads.
Definitely need metal for these pressures.
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Those are impressive numbers with FPEs in the 130s. I only see FPEs around 100 with the 18″ barrel and 120 max with the 24″ barrel and the 6-rings. The first 15 shots or so of my strings are within 25 fps of max though and 20 shots within 50 fps. Then it falls off pretty fast. I like the consistent shot count though for 20 shots.
The first 5 shots with 50 grains are giving only 95 FPE with the 18″ barrel (50.8 grains and 917 FPS avg). I was looking for over 900 fps with the short barrel so that is good enough. The issue now is accuracy. I want to get real close to 1 MOA at 100 yards with cast slugs but it appears that the right .25 ACP 50 grain slugs sized optimally may be necessary.
Most of my game shots are under 50 yards so the Surefires are fine most of the time but there is a clearing in my backyard that gives the opportunity to pick coons off coming in along a trail from the creek bed that gives shots in the 75-120 yard range. If I can get an accurate slug close to 1000 fps (24″ barrel) with 50 grains that would be perfect.
I was messing around this morning and ran into some breech problems. Need to make a aluminum breech if I want to push the 9 rings with my other valve. Delrin one I made got bent sideways and pulled the cocking knob threads out from the extreme pressure against it. I did get some improvement on numbers. The only shot I got with my other valve was 816 fps with a 9 ring on 2500 psi fill.
973 fps 6 ring
929 fps 7 ring
856 fps 9 ring
1094 43 gr eungins
I loose 10 fps per shot on top. It levels off and becomes less. I’m firing it without a shroud and can’t unload that many shots right now to find where it levels off. Sounds like I’m firing a 9mm hand gun in the garage.
I would like to get the new valve/breech setup for the .308 R&L is doing and test that on the .25s but I suspect it would take a specially machined barrel. I think it only gets about 5+ shots but they should be strong.
I started testing with the 18″ barrel, R&L valve and the 50 grain Surefires. I am shooting through my chrony on target and the first 5 shots got about a 7/8″ group at 50 yards which is comparable to the uncut 6-rings. Velocity is up about 65 fps. the 18″ loses about 100 fps (compared with the 24″) but it is short – especially with the shroud off and and I prefer it in the field. Fill to 3000 psi. I will finish the tank and get the string.
Marvin that # 632 looks interesting if you had the mold shortened to take off the gas check base.
Regards,
Roachcreek
Thanks for joining in, are you using one f the NEI designs, that one you have on order looks intersting.
NEI has moved around and changed hands a few times, when I lived up on my remote mountain, they were close neighbors to me, well 78 miles was close.
I got spoiled because I could go down and talk to the original owner, Walt, and search his mind for designs. I had a 3040 Krag 220 grain mold, a 320 44 mag mold and a 40 S&W mold that I got from him.
Welcome aboard,
Regards,
Roachcreek
Yes, I’m using NEI mold.
And have standard choked LW barrel.
I’m wondering about 31.5″ barrel
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And because of Marvins handwriting in his notes, we are all wondering if Marvin is a physician. 😆
Which beats me of course, I usually don’t write anything down unless here. Butcher did get me to get a logue book for the Ranger 45 perhaps I need one for the 25 ACP cast bullets.
Regards,
Roachcreek