Condor for shooting cast boolits?
Boattail boolits have a 3 times advantage in Ballistic coefficient and theoretical 3 times advantage in cross wind group size. But boolits are heavy and need more spin than pellets. The Condor can easily develope enough energy to throw a 51 gn boolit at 850 fps but Bob’s new design requires at least 1:16 twist for optimal stability and Walther lists the airgun barrels at 1:17.7 which might not be enough for this design. I’m thinking of buying a new Condor SS for shooting home cast boolits. Can someone here measure the twist rate of the stock barrel by pushing a patch through to see how far it takes for the rod to go 1 revolution? Here is the link to the new mold design.
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http://www.gatewaytoairguns.org/GTA/index.php?topic=58933.0
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Viewing 14 replies - 1 through 14 (of 14 total)
You will need bushings made also.
.25 auto barrel is .558″-.560″ OD.
She wrote back to me to correct herself. The AirForce barrels are 1:17.7. That’s ok. A TJ’s forged barrel is less than $100.
I wonder if any sellers would sell me a Condor SS and keep the barrel. Or if I could sell the 18″ .25 barrel unfired for a decent price. Maybe someone with a Talon would want it. They are $170 at PyramydAir.
If you cut the choke off of a LW barrel it will slug around .25400″. The only real way to shoot slugs is to use a TJ’s .25 auto barrel.
Then you can shoot pellets and slugs.
I also see that LW specs the .25 airgun bore at .248/ .254. I wonder what they really measure before and after the choke? I thought I saw one post where they measured .251 before and .250 after the choke. The new 52gn boattail bullet mold is designed around .243/ .250 for a 14 twist .25 ACP barrel at 1050 fps.
The choke is still an issue. I would suggest talking to talon tunes or rlsupply.
Next time someone is cleaning their Airforce barrel, maybe they can take a rough measurement by watching the twist rate of the rod and let us know for sure. LW is known to be incorrect on their speced vs actual twist rates as stated by one of the gun smiths. Even when they have the same stamp markings.
Well according to LW who make the barrels that AF uses, they don’t have a 1-16 barrel.
I emailed Airforce and they say the twist rate is 1:16 so they might work well enough with the boattail boolits.
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Hi Scott,
Thank you for your inquiry. The twist rate for our barrels is 1:16. That includes the 18” 12mm barrel for the CondorSS. Please feel free to contact us with any further questions.
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I’m watching to see what comes out of this thread but would probably just end up buying a more suitable barrel such as the 25 ACP liner barrel that Bob designed this mold for.
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http://talonairgun.com/forum/viewtopic.php?f=1&t=28473
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Also watching here.
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http://talonairgun.com/forum/viewtopic.php?uid=100149&f=10&t=28399&start=0
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Sorry. That is not correct. Ballistic coefficient has a 1:1 relationship windage. If a bullet is 4 times more aerodynamic than a pellet, a cross wind will push it over 4 times less. A JSB king .25 at 900 fps has a ballistic coefficient of .0360. A Bob’s boattail cast bullet at 850 fps has about .1250. Chairgun shows a 10 mph crosswind will blow the JSB over 7 inches at 75 yards. The boattail bullet windage is less than 2. But the skirt on the pellet keeps it from tumbling like the fins on a dart. A boattail bullet needs much more spin to keep it stable so if the Walther barrel has a twist rate of 1:17.7, these bullets won’t work well without changing the barrel. If it is 1:15 like a Marauder they will be perfect. Look at the table under the column for “drift in inches”
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Yeah, but only at supersonic velocity. Shape only becomes critical above the speed of sound. In pellet guns a hollow base that allows expansion under firing pressure is valuable.
John
LW barrel won’t work, it has a choke, unless you cut it off, even then a 1 in 16 twist is too slow.
Research the MASSIVE amount of data on this forum re: slugs….
Viewing 14 replies - 1 through 14 (of 14 total)
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What the heck… LW is specifying a .254 bore choked to .248 now? That sounds like a problem to me; I don’t size my slugs .006 in a nice, lubed die! I know LW had a quality issue but I had hoped they were over it. Slugging a barrel isn’t hard, owners should learn what they have.
BTW, I have designed and made some round nose, boat tail slugs for my .32 guns. The velocity at range confirms the aero efficiency but the story reveals other variables. One of my .32s does not like the slugs that much at all, the other shoots them at .3 MOA @ 100 yards! The accurate gun only likes the slugs when loaded backwards though! The barrels have minor differences and both have shot below .4 MOA @ 100 yards. There’s a lot more to accuracy than just aero performance. For my guns, I think the difference comes down to chambering.