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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No I haven’t checked. I know I get over 20 shots abov 1000 fps with eunjin’s. I spend most of my time messing with regs. I have figured them out and now I will play with trying to make more consistant power. I’m going to try something tomorrow and I’m hoping to push the 9 rings close to a 1000 fps. As far a the Blod valve goes, if I opened up the ports like R&L did to the condor valve I’m sure I can get 50 fps more. I just can’t call up and get a replacement like I can if I break a condor valve. Once my lathe arrives here in the next couple of weeks I will be able to make my own valves and valve parts. I think the Condor valve is limited. I cannot get one to shot as hard as the blod valve unless I make it unreliable.
I am looking but I did those two months ago. I remember you bought that Blod valve and It sounds like it may have an efficiency issue?
I am only shooting the 6-rings at 850 fps/100 fpe and I think you were shooting them about 100 fps higher and I wonder how much air is being wasted. I am hoping to get arounf 910 fps with the 50 grains but I want to rerun all of those numbers again before I post anything.
Do you know the psi/fpe for the Blod valve setup ypu are using? I want to calculate efficiency numbers as well.
You said u get 20+ shots what is the start and finish fps right now.
Thats what we are going to find out. I will testing a Condor w an R&L Extreme valve and both an 18″ and .25 24″ barrel comparing 51 grain and 62 grain Surefires for velocity and accuracy.
What fps to what fps?
I get 20 +shots right now but would get less if I maxed it out. I want more velocity w/o wasting more air i.e. lighter slug.
Shot count? You have to run it wide open to shoot the slugs. You think your going to be able to back of I highly dought it. Your lucky to get 10 desent shots on stock tank. If your worried about shot count you need to run a larger tank.
Shot count. I am already using an modded (Extreme) valve and getting about 100 fpe with the 6 rings and an 18″ barrel. Looking to flatten trajectory and increase velocity somewhat for longer range. For opossums and coons more power really isn’t needed. The 51 grain .25 ACP with sizing is probably the perfect slug.
So much work for 10 gr. Why not bump the power up on your gun and just shoot 6 ringers.
Of the 32 slugs I machined 29 of them were either 50.6, 50.7, or 50.8. 3 went 50.9 and I will reduce those back 2/10 from the center of the back. They were cut so that the length of each was within .001 so the weights should have been very very close (probably closer than they started as 6 rings).
After studying the castings under a magnifier I am a bit surprised the Surefires fly as well as they do for me. I guess the rings are large enough that the rifling and choke is cutting/molding them quite a bit.
Weight?
Here are a couple of the Surefires I machined down next to a 6-ring.
Thats where I just calculated the fpe as well on that site. My machinist buddy created a jig so I am going to his house to machine down about 30 6-ring 62 grainers in a while. The milling bit should make them perfect clones of each other and create a uniform and repeatable bullet base.
I think that the ringed bullets should have less barrel drag than the pistol slugs but I may be wrong. 🙂 In flight is another story though and I would think the pistil slugs BC might be higher than the draggy rings.
My buddy also looked over the Surefire slug I gave him and he said it’s specs are very rough and it mic’s different diameters all over the place. It’s not sized or anything. I would think the pistol slugs would have the potential for better accuracy.
Secoda,
I use Handloads.com Ballistic calculator to get all my BC and trajectory information. It shows the BC for the .25 50 grain at .113 and the 52 grain at .118.
It was extremely close on my 45 Ranger ballistics.
The best molds for true bases I have had, were nose pour molds from Hoch for that very reason.
Regards,
Roachcreek
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I have tried several combinations again today, ranging from the Airarcher parts to stock Condor with the RL extreme valve stem and with both the 103 gram Subsonic hammer and the Condor hammer and weight.
With going all Condor parts except the RL valve stem, I find I can shoot both the Kings with a PW setting of 10-1 and if I max it out I can get up to 966 FPS with two Kings.
I tried using the 103 gram hammer, and while I can get the velocity down to below the speed of sound, the extra impact of that big hammer hampers accuracy in my rifle.
Shooting a string with a 3000 PSI fill, and that is like guessing, I have several nice big fairly new gauges, they all read differently, so when I say 3000 PSI, take it with a grain of salt, one gauge was reading 3000 another was at 3400 PSI, but I started out at 860 went up to 965 and then back down to 860 in 15 shots or so.
I tried a heavier spring, a old one out of a 1st generation Airarcher kit, but it was a little too strong I think for what I was using.
So right now it looks like all Condor parts except the RL valve stem and what may be a 3000 PSI fill.
Hpefully my bullets will be in Monday and I will see if this all works out.
Regards,
Roachcreek