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
All Replies
RC,
When did you get the R&L valve?
Syn,
How would Brass insert affect the tophat setting?
Assuming the valve retainer and valve spring are installed properly:
The derlin valve seat can affect the distance the tophat sticks out of the brass insert, however if the stem is not seated all the way into the derlin valve seat, if not seated all the way into the derlin peice, it will have a greater tophat clearance. But how far the valve insert is screwed into the valve body would not make any difference.
For your information:
I took both valve stems and screwed both tophats on, measured them, exchanged tophats onto the other valve stems, measured them, put them both in the brass insert, measured each combination. I did all this this morning before shooting the gun.
THe RL valve stem and top hat, without the derlin seat, outside the brass insert measured 1.46, the AF measured 1.55, the RL stem with AF tophat measured 1.52.
Both my particular AF and RL valve stem by themselves are the same length, so it is how far the RL tophat screw onto the valve stem, regardless of the maker of the valve stem that determines tophat clearance.
I have two Condor brass inserts, they are the same size inside and out.
So the only way I can see that this is explained is that my particular RL tophat has a larger thread stop inside it and stops the top hat from screwing out as far as my AF tophat or Secoda’s tophat.
Regards,
Roachcreek
I’m wondering if the brass seat face hasn’t unscrewed on RC’s valve and causing a low top hat setting…
Randy has it posted that the TH is set at .088 on the extreme valve.
http://www.rlairgunsupply.com/cart/products/Stubby_Extreme-749-131.html
My brand new Condor tank is set at .095
😕
Uh, factory setting is typically 0.110″, i’ve even set mine out further without any problems… I could have set it further than 0.120″ and still have the screws bite just fine. 😉
Ok, just tested a Condor top hat.
Full extension: 0.162″
I detuned my Talon valve but never set it smaller than 0.07″
I was talking to Randy and it was interesting that he says his valve is designed to work with the stock Condor hammer. Going to a heavy hammer is not recommended, so I can see that the .065 top hat clearance is the normal setup. Somehow the RL valve has a whooping inner cavity and or somehow increases the valve efficiency.
If you run the numbers on a 62.7 gr 6 Ring (hypothetically all else being the same):
95 gram hammer (Tony) and stock valve (61.62% efficiency)
62.7 gr at 749 fps = 78.1 fpe
To match that FPE, one would need a
65 gram hammer (stock) and RL valve with 82.3% efficiency.
My RL tophat is different than the AF tophat, but it is not fixed, it has only one set screw, and the set screw seems to be a different size than the .050 used on the AF tophat. I can’t really use the set screw, so I locktite it to the stem, which I do anyway with all my tophat/valve stems.
Syn, check the sticky’s on tophat adjustments, they range form .1 to .070.
Regards,
Roachcreek
Looks identical to mine but Hoot and I got ours about the same time.
Can I see a photo of the R&L tophat? 😀
I take it it’s fixed?
Isn’t this the R&L Extreme (lower valve) and Condor side by side…? Is the Stubby Extreme valve different than the Extreme?
I just talked to my buddy and he is creating a split holder for the .251 Surefires so I can trim the same amount off of the bottoms with a milling bit inbetween the rings that is adjustable for the depth. He said it will be a quick grip that barely snugs the bullets and he has done this with pistol slugs b4 w/o issue. The cut will be on the back between the last two rings and should cut the weight by about 10 grains. He thinks I should be able to do 50 slugs or in less than 30 minutes with the quick grip. I may do 25-30 just to test the accuracy.
I may order up a few hundred more 6-rings. I have shot 3 opossums with the 6 – rings now and they have all ripped right through and one was a rear angling shot so the 52 grains should be more than enough mass. I shot two opossums with the 26 grain Predators and neither went more than 7 feet but they don’t exit.
THe R&L TH is .088.
Don’t you mean 0.1650????
0.0650 is not even close to all the way out unless the brass retainer is also proud of the valve… 😕 0.0650 is extremely if not dangerously close to the brass for high power whacking of the hammer/breech assembly…
Can you post a photo of the tophat/valve? Isn’t the R&L tophat just the Condor tophat? 😕 😯
Yeah, my RL top hat never went beyond .065. By using the AF tophat I can screw it out all the way.
I have also thought it odd that I can only open the valve fully with a 2500 PSI fill, perhaps a valve impact problem, the spring is over 2 years old and had thousands upon thousands of shots thru it.
So it is probably the RL tophat on mine that is restricting it to .065, I don’t want to put much force on it trying to get it to go out further and damage it.
But at 1065 it is going as fast as you can go with Kings and not get eratic accuracy. With the AF tophat and the 103 gram hammer I get 1165 which way too fast for the Kings, but it does in fact open the valve fully at 3000 PSI.
I used the Airarcher valve retainer to try and avoid bottoming out the valve stem and breaking it.
But I have to tell you, I am okay with the 944 FPS and the 52 grain bullet, but accuracy will be the deciding factor here, and I can always revisit the Airarcher fire control system. I may even settle on a 1065fps King/850fpe 52 combination so I only have to adjust the scope to change loads.
It is all fun, especially being able to make my own bullets. I like hunting with my own bullets, I have killed some nice bulls in my 50 head of elk, but the ones I killed with my home made bullets were my real trophies regardless of size.
Regards,
Roachcreek
RC,
Something sounds funky. I am using the R&L valve but the TH is as Randy adjusted it at 88 and PW at 12 and am getting 850 fps out of an 18″ barrel with 6-ring (62 grain) Surefire.
I am also pursuing a 50-52 grain slug and was hoping to push velocity up over 900 fps for a bit better long range trajectory even if the fpe falls from 100 down to 94-95 or so. My machinist buddy says he can cut the backs off (the last ring) of the 62 grain Surfires and tweak the weights within 1/10 of a grain. I’d would be interested in also persuing whatever you guys get going for 50-52 grain slugs.
[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. ]
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Secoda,
THird week of July this year.
Regards,
Roachcreek