I come from a long range bench rest powder burner background in another life. Wether shooting at 200 yards 300 500 or a 1000 yards. Velocity ballistic coefficient and barrel twist rates were very important. I am awed by the performance of modern big bores tethered with high quality cast slugs. I just don't understand why the airgun community isn't chasing ballistic Coefficient shooting under 1,000' per second even fast twist rates aren't really gonna stress you're slugs like at the ultra high velocities that powder burners run. My 1-26 twist .510 Texan will run 1.375 inch long 650 grain spire point boat tail more accurately than anything else. The wind is horrible at subsonic velocity s and big bores just shoot heavier lead at 1000 fPs as the technology and pressure increase. So why are not chasing b.c to help with the wind and down range energy. Example. 308 Texan air gun could be shooting a Lee 230 spire PT boat tail with a b.c. of .6. If it had a 6.5 or 7 twist. Or .257 Texan with a 1-7 twist and a noe mold 115 gr spire PT bullet. Are velocity are so slow I really dnt think we really need slow twist rates . if you can shoot a .224 80 yr bullet out of a powder burner at say 3300 fps in a 8 twist and the bullet doesn't explode. 300 blackouts run the same cast .308 slug as the air gun community say 190 to 230 grain at subsonic velocity with 7twist barrels and have zero problems. This is my best attempt for b.c for now. 
Highest Ballistic Coefficient air gun Slug ?????
- Thread starter RM.510bigbore
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i think most want effective hunting rounds, which are not going to expand as well with a pointy tip high bc slug at airgun velocities, maybe?
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Not everyone. I had my .257 Scandalous made for 300+ yard group shooting explicitly. I'll probably take it groundhog & yore hunting but the 72 grain slugs at 1080 are from a Lilja barrel. Everything about it is for rigid platform repeatability. It's shot tethered with a step down in-line reg,
BC for the 420257 is only .212, the 1:10 can handle the Griffin 4S & probably lighter 6S that they offer.
Edit: Will hopefully have it by upcoming weekend.
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that's why i said most. some of you guys are stretching distance and shooting for groups, but i see lots more people hunting than shooting for groups.
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It can be a balance between BC and velocity with a ceiling of factory barrel twist rates.
What velocity are you getting with that bullet in your .50 cal Texan?
What velocity are you getting with that bullet in your .50 cal Texan?
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750 fps factory TX2 valve . I want full pass throughs on my hunting rounds. I dnt like not having a blood trail. Hollow points do kill well but in my experience no blood trails. I'm just looking forward to the future of the sport pushing it limits. Its awesome to shoot any air gun and slug combo to your long range destination no matter the b.c. and power. Air guns are so much cheaper to shoot and neighborhood friendly than powder burners it going to the only option to keep shooting. 14 twist barrels with short bullets are very accurate. I think your 257 Texan 14 twist is similar in the bench rest world of 6ppc and 6br shooting 68 to70 yr bullets..
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Here's some thoughts of mine, correct or not, because I can't say for sure not being a ballistician.
I remember way back more than a decade ago when a guy named Dean was testing at night for the development of the 408 and 375 Cheytac using precision lathe turned solid bronze alloy projectiles for ELR. He noted that banded projectiles had more drag than straight walled bullets like most powder burners use and the banded projectiles would hit much lower at extreme distances. He named them DRAG bands. So this being supersonic my question is are banded lead bullets at sub sonic velocities affected near as much??? I never used a banded solid projectile but those 350gr Hooker Tactical 375 cal solids were incredible for extreme distances in my 375CT!!! G1 BC was around .9 going 3250 fps.
Next question is if we had LONG lead bullets that were not banded would too much resistance be imposed in the barrel for a pcp?
I had a 300BO and used Berger 230gr hybrid copper jacketed match bullets with a .7-ish G1 BC at 1050 fps. I still found it NOT easy hitting 2 MOA steel past 300Y due to "wind" and drop. By 400Y it got pretty difficult.
But the more the BC, the less the wind drift, and drop, at the same speed of a lower BC projectile.
I'm interested in using the least air possible and don't need super heavy lead bullets for shooting steel at longer distances with a pcp. I would like to see stiff actions and heavier match barrels more for shooting steel and targets, along with higher BC lead bullets in the .5 - .6 G1 BC area. That shouldn't too hard to do in 6.5-7mm caliber "I think" ???
I remember way back more than a decade ago when a guy named Dean was testing at night for the development of the 408 and 375 Cheytac using precision lathe turned solid bronze alloy projectiles for ELR. He noted that banded projectiles had more drag than straight walled bullets like most powder burners use and the banded projectiles would hit much lower at extreme distances. He named them DRAG bands. So this being supersonic my question is are banded lead bullets at sub sonic velocities affected near as much??? I never used a banded solid projectile but those 350gr Hooker Tactical 375 cal solids were incredible for extreme distances in my 375CT!!! G1 BC was around .9 going 3250 fps.
Next question is if we had LONG lead bullets that were not banded would too much resistance be imposed in the barrel for a pcp?
I had a 300BO and used Berger 230gr hybrid copper jacketed match bullets with a .7-ish G1 BC at 1050 fps. I still found it NOT easy hitting 2 MOA steel past 300Y due to "wind" and drop. By 400Y it got pretty difficult.
But the more the BC, the less the wind drift, and drop, at the same speed of a lower BC projectile.
I'm interested in using the least air possible and don't need super heavy lead bullets for shooting steel at longer distances with a pcp. I would like to see stiff actions and heavier match barrels more for shooting steel and targets, along with higher BC lead bullets in the .5 - .6 G1 BC area. That shouldn't too hard to do in 6.5-7mm caliber "I think" ???
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I too am chasing long range accuracy and looking for a higher bc slug. Altaros makes a round nose with a bc of .21 but it's not available in the US :-(
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You are correct most cast molds have grooves designed in them for lube. You don't have to have the lube grooves if you powder coat. That mold with the 650 spire PT bt only has 2 shallow grooves. Probably who ever designed it for regular fire arm cartridge and the groves are where the crimp or seat to. I'd like to get another mold with no grooves at all. I didnt wanna try to special order something when they where 6 weeks wait already. Hopefully the mold manufacturers like accurate and noe are getting caught up. In my mind I'd just like to have cast slugs copying hornady eld x . same weights and b.c in a powder coat pure lead cast form. 
if it is possible that is. I have a cold shot 144 mil adjustable base coming!!!!!!! Can't wait to actually shoot long range even if only at 750 fps hopefully can get a decent b.c figure.
if it is possible that is. I have a cold shot 144 mil adjustable base coming!!!!!!! Can't wait to actually shoot long range even if only at 750 fps hopefully can get a decent b.c figure.Upvote 0
I doc. .21 b.c. is no slouch at all. That's a nice looking slug. Hopefully you can get some
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I need to make a correction. You can have the Altaros slugs shipped here. It is just expensive. My frugal (i.e. cheap) brain was telling me it wasn't possible. I might have to break down and order some.
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I'm sure you can make a group order to save on shipping.
AGN is the right forum for this, too -- because here we have so many SLUG NUTS...!!
Matthias
(guilty as charged)
AGN is the right forum for this, too -- because here we have so many SLUG NUTS...!!
Matthias
(guilty as charged)
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JamesD,
James you mention the .257 Scandalous, the first I heard of a .257 scandalous, quite a few years ago, was a Jack Hailey production. By any chance is this one of Jack's guns? They were very accurate. One guy, don't recall the name, but would often shoot moa groups out to 200-250 yards with his.
Anyway just wanted to inquire as the name ".257 scandalous" caught my eye.
Cheers
James you mention the .257 Scandalous, the first I heard of a .257 scandalous, quite a few years ago, was a Jack Hailey production. By any chance is this one of Jack's guns? They were very accurate. One guy, don't recall the name, but would often shoot moa groups out to 200-250 yards with his.
Anyway just wanted to inquire as the name ".257 scandalous" caught my eye.
Cheers
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There are diminishing returns of ultra-high BC ammo with airgun velocities for airgun hunting. The higher the better obviously if your barrel(s) can shoot them accurately, but I'd question the ethics of taking a shot at anything at or larger than a coyote where that extra BC would actually produce any substantial drift minimization.
I just started tinkering with my .457 Texan carbine (TX2). Testing 240gr NSAs (0.178 @873fps) and the 500gr banded SP (0.238 @655fps) from Hunter's Supply. I can see taking a large animal with that rifle at 100y, but I would much rather have the velocity behind it with the lower BC ammo at that range - there just doesn't seem to be any major difference in drift between those at that ethical range, yet one hits the target much faster than the other.
I haven't shot any ammo from an airgun that required a 7" twist, but I'd doubt something like that would be accurate in low subsonic. My experience has been that each barrel twist used for a given high BC projectile has some sweet spot velocity range(s), but you have to shoot really fast to get any mileage out of anything faster than 16" with an airgun.
The .25-.257 range is definitely nice for airguns, but I've had stellar luck with .217 40gr 2S RBTs in 16-17.7" twist barrels in high transonic - low supersonic with virtually no drift at 100y, and extremely manageable drift to at least 250y in nasty variable winds over uneven terrain. BC is 0.161-0.163. The rifle + ammo feels neck to neck with .22 Lapua. Worth noting that the 4S nose version of that projectile with those barrels is flat out dangerous in terms of instability.
It really comes down to having a good barrel + projectile match x realistic power to shoot them with. Gas pressures for airguns are nothing like fieearms, but obviously the harder you push an airgun - the harder it will be to shoot accurately in some real world setting.
You might want to do a small test order first. I wasn't impressed with their banded ammo. It was grossly undersized from what I ordered and took 6-7 weeks to deliver to the USA. Quality was maybe a 1/2 step above cast MP moulded slugs.
I just started tinkering with my .457 Texan carbine (TX2). Testing 240gr NSAs (0.178 @873fps) and the 500gr banded SP (0.238 @655fps) from Hunter's Supply. I can see taking a large animal with that rifle at 100y, but I would much rather have the velocity behind it with the lower BC ammo at that range - there just doesn't seem to be any major difference in drift between those at that ethical range, yet one hits the target much faster than the other.
I haven't shot any ammo from an airgun that required a 7" twist, but I'd doubt something like that would be accurate in low subsonic. My experience has been that each barrel twist used for a given high BC projectile has some sweet spot velocity range(s), but you have to shoot really fast to get any mileage out of anything faster than 16" with an airgun.
The .25-.257 range is definitely nice for airguns, but I've had stellar luck with .217 40gr 2S RBTs in 16-17.7" twist barrels in high transonic - low supersonic with virtually no drift at 100y, and extremely manageable drift to at least 250y in nasty variable winds over uneven terrain. BC is 0.161-0.163. The rifle + ammo feels neck to neck with .22 Lapua. Worth noting that the 4S nose version of that projectile with those barrels is flat out dangerous in terms of instability.
It really comes down to having a good barrel + projectile match x realistic power to shoot them with. Gas pressures for airguns are nothing like fieearms, but obviously the harder you push an airgun - the harder it will be to shoot accurately in some real world setting.
You might want to do a small test order first. I wasn't impressed with their banded ammo. It was grossly undersized from what I ordered and took 6-7 weeks to deliver to the USA. Quality was maybe a 1/2 step above cast MP moulded slugs.
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I didnt read the whole post before answering, sorry!
But food for thoughts: The 50BMG is a scaled up version of the venerable 30-06, exact measurements just scaled up.
So why not scale up the best BC cast bullet that is avaliable in .30 cal?
The Lee: TL-309-230-5R
https://leeprecision.com/mold-dc-tl309-230-5r.html
A true and tesed BC of some .688
But food for thoughts: The 50BMG is a scaled up version of the venerable 30-06, exact measurements just scaled up.
So why not scale up the best BC cast bullet that is avaliable in .30 cal?
The Lee: TL-309-230-5R
https://leeprecision.com/mold-dc-tl309-230-5r.html
A true and tesed BC of some .688
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