My Condor Builds

[dyotat100]

Thanks

There are 2 1144 materials. One is stress proof and says 100,000 and there is shock proof that says 125,000.

I will use the shock proof.

[rsterne]

Is that tensile strength, or yield strength?....

Bob

[dyotat100]

Says yield strength.

[dyotat100]

Did a little casting today.




 Cast 600 257-420 and then made a new sprue plate with smaller holes and cast 650 with it. New plate has .108" compared to .150" that it came with.

[rsterne]

Nice looking boolits.... I've found that the sprue hole shouldn't be larger than 50% of the diameter of the base or you can get a distorted/squashed corner....

Bob

[QVTom]

Another interesting material is 7068 aluminum, it has a yield of 95,000 psi and is available in round bar.  It's generally referred to as ordinance grade; maybe not the best moniker for a pressure vessel.

https://online.kaiseraluminum.com/depot/PublicProductInformation/Document/1033/Kaiser_Aluminum_Alloy_7068_Brochure.pdf

[PakProtector]

The small sprue plate hole is catching on... be nice to see Lyman and RCBS split it up that way...25 and below get .1" plates and the rest can get bigger. It sure makes a diff for the .224 stuff, but it was the 25 auto stuff that got my notice...the size witness would be missing a crescent of area upstream of the sprue cutter where it had effectively bent the boolit on the cut off.
cheers,
Douglas

[dyotat100]

Yeah I have been doing it for awhile. Ever since I bought a mold from Veral and saw how small his holes were.

I have a Lyman 4 hole .308 mold that I have .104" holes on and it makes perfect bullets also. I also have a 4 holes Ideal 257420 mold that has .175" holes. Uses the same plate as the .308 does. I used the plate from the .308 but still had issues with bullets not coming out perfect so I'm still using my Lyman 2 hole mold. Was hoping I could use a 4 hole mold on that bullet because it is what i shoot the most.

 The 4 hole 118 gr .308 is my best bullet so it worked out there though.

I have also done it for a 4 hole NOE 257 mold for someone else and it made it work great. Opens with your hand instead of a hammer.

[dyotat100]

Here you go Bob.

70 ci tank
83.3 gr

3490-1020 fps
3448-1028 fps
3404-1031 fps
3361-1038 fps
3318-1031 fps
3274-1027 fps
3228-1028 fps
3172-1028 fps
3120-1019 fps
3070-1020 fps
3022 ending pressure

10 shots 468 psi

Here is my setup. Gauge is +- .025%


 

Also got 1083 fps with 94 gr 4000 psi for 244 fpe

[rsterne]

I didn't calculate the average, just guessed that it was ~1025 fps (194 FPE) so a total of 1940 FPE.... 468 psi / 14.5 = 32.3 bar x 70 CI = 2259 CI.... Efficiency = 1940 / 2259 = 0.86 FPE/CI.... pretty decent, but I've never run a gun at those pressures to compare....

Bob

[dyotat100]

Thanks

I threw out 1,9, and 10 and I came up with 97.

That was my first attempt at a curve. If I spent some time I could get a better curve.

Once I get a 4500 psi setup I will play with it some more. If I have time I will change out the hammer spring and do a curve with my 3000 psi tank. I will do 5 shoot string from now on.

[rsterne]

I threw out 1,9, and 10 and I came up with 97.

No idea what that means (the "97").... I don't see anything wrong with a 2% ES (2% of 1038 = 21 fps, so a low of 1017) for shooting at about 100 yards, the vertical stringing should be minimal.... and you're within that with the string you posted.... It would be interesting to tether the gun to a 3000 psi regulator and see what the ES is that way....

What weight did your 257-420s cast at?.... The ones I did using 1% tin were 73.5 gr.... I have one cavity converted to a Hollowpoint and it drops at 66.0 gr....

Bob

[dyotat100]

97 fpe/ci is what I got dropping 1st, 9th, and 10th shot. I will be making a reg setup also and set the reg around 3000-3200 psi.

Should be able to get 25 shots on 4500 psi tank.

I have HP 420 mold also. It drops 69.4-69.5 real consistent.

Regular 420 mold drops and 73.9-74.3. Most right around 74.
This is with pure lead.

Here is a NOE mold that has been shaved down and now produces 67 gr HP and 71 gr regular.

I poured these last night.


 

[rsterne]

I just noticed a problem with your pressure data, which would cause you to get different results.... You missed reading the pressure after shot 8, the pressure dropped 102 psi instead of 50ish.... for 10 shots you should have 11 pressure readings.... 3490 - 3022 = 468 (about 47 psi per shot).... If you drop out the 1st, 9th, and 10th shots, the starting pressure is 3448 but after the 8th shot the pressure should be about 3121 psi, not 3070, that would be after the 9th shot, and 3022 after the 10th....

So for 7 shots @ 1030 fps (196 FPE) = 1372 FPE.... pressure drop 3448 - 3121 = 327 / 14.5 = 22.6 bar x 70 CI = 1579 CI.... 1372 / 1579 = 0.87 FPE/CI....

Bob

[dyotat100]

Yep no pressure after last shot.

[rsterne]

EDITED above - I found the problem....

Bob

[dyotat100]

Thanks. I fixed it on original post.

You were close. I went out and dug the paper out of the trash. It is  3120 psi.

I'm liking all the technical info and support here. Anybody good with how to build a good trigger setup?

I'm going to build a complete condor frame setup for .457. The trigger is my only issue and would like to do something better.

[Scott Endler]

I believe RL airgun supply offers a read to shoot .257 Condor.
.
http://www.rlairgunsupply.com/custom-shop-page-2/

[dyotat100]

My post says .457. I'm building a COMPLETE gun, frame and all.

What R&L offers is not a real .257. It is still powered by a .25 condor valve.

My .257 barrel has a .375" breech and the valve has a .280" ID.  Condor valve is .247" OD .217" ID.

[Scott Endler]

hit a couple golf balls at 110 yds.

Maybe next time out you can shoot some paper so we can tell something about the accuracy.