GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Big Bore AirGun Gate => Topic started by: YEMX on May 31, 2025, 05:25:48 PM
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I'm starting to wonder if "weird ideas" is all I have anymore LOL
Anyhoo, I'm kicking around a .308 pistol/carbine build. 16" barrel. I know- that's really short. I'm looking at NSA slugs (plus molds for slugs in the same weight range), so 65 gr, up to 105 gr. Heck- maybe even up to 120 gr. My question is, twist rate. Thoughts on that? I won't be shooting pellets at all, ever. Just slugs and cast boolits. I know, LW has a 1-14 twist. Again- just wondering what everyone's thoughts are. TIA!
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.308 and not .300 ?
Short barrel, slow speeds you need to look at projectiles and weights for those two respective calibers ?
I would go .30 as the lessor weights and shorter length is far better pistol suited IMO.
I've got a TJ's in .30 with 1-9 twist that's too fast of twist for rifle speeds and short projectiles, tho might be killer for a pistol based rig ?
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.308 and not .300 ?
Short barrel, slow speeds you need to look at projectiles and weights for those two respective calibers ?
I would go .30 as the lessor weights and shorter length is far better pistol suited IMO.
I've got a TJ's in .30 with 1-9 twist that's too fast of twist for rifle speeds and short projectiles, tho might be killer for a pistol based rig ?
.308. The project is based on a Texan. So I guess it's not REALLY a "pistol" LOL
I guess my main questions are, with such a short barrel, with those light-ish slugs, would a faster twist rate be better? If so, how fast?
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The old 32 cal (.312) pistol rounds used a 1:16 twist and had relatively low velocity with 90gr range projectiles.
32 long Colt as an example.
The faster 32-20 used a slower twist, with longer projectiles and it worked as well.
Just something to consider to be able to compare to.
Dave
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Hmmm... The slowest that's commercially available (that I can find) is a 1-15. The LW is 1-14... But the LW isn't what I would call a "true" .308, it's an oddball one, going off the specs from their website. Also, I want to start off with a larger OD blank.
The lengths of the projectiles I'm looking to shoot vary of course, from .400" all the way up to .593", I'd also like to lean towards the heavier slugs- so the .500"-.593" length ones. Not sure if that info will help in the decision making process...
Again, thank you all for your input!
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Got nothing more as this has / is going outside my wheelhouse of knowledge.
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Since you are wanting to lean to the heavy side of the projectiles, the 1-14 should suffice…without being detrimental to the lighter stuff.
Finding the perfect barrel these days for odd applications can be a pain. I learned this during my powder burner building days.
If you did go with the lw, you could always sleeve it up in size. How large does the od need to be?
Dave
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Got nothing more as this has / is going outside my wheelhouse of knowledge.
No worries! Thanks for following along! 8)
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Since you are wanting to lean to the heavy side of the projectiles, the 1-14 should suffice…without being detrimental to the lighter stuff.
Finding the perfect barrel these days for odd applications can be a pain. I learned this during my powder burner building days.
If you did go with the lw, you could always sleeve it up in size. How large does the od need to be?
Dave
Oh, it's not a "need" LOL If I decide to use the factory barrel (which would be the cheapest option of course), I wouldn't do a thing to it, except make it shorter, and perhaps cut off the feed trough. The only reason for going with an aftermarket barrel is because it'll be a "true" .308 spec barrel. I'll do some more digging to confirm this. I'll post up what I find, to get y'alls opinion.
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Fwiw, lothar seems to have a true .308 groove, .300 bore in the powder burner section. Expensive (imo) and would take a lot of time on the lathe to thin down……
Keep us updated
Dave
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And maybe something to tame the muzzle blast.
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My recent idea was way weird. A friend gave me 2 10# down rigger weights to melt down for ammo, I'm looking at 2 round balls thinking why melt them down when I could find a barrel they would fit in ??? Just need a 1000cc plenum etc.. LOL
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Love it !!!!
Shoulder wont if you fired a PCP that could !!!!
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Love it !!!!
Shoulder wont if you fired a PCP that could !!!!
Small cannon mounted on skids comes to mind ;)
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My recent idea was way weird. A friend gave me 2 10# down rigger weights to melt down for ammo, I'm looking at 2 round balls thinking why melt them down when I could find a barrel they would fit in ??? Just need a 1000cc plenum etc.. LOL
Heck yeah!
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Fwiw, lothar seems to have a true .308 groove, .300 bore in the powder burner section. Expensive (imo) and would take a lot of time on the lathe to thin down……
Keep us updated
Dave
Actually, those blanks are cheaper than what I would be spending on a custom blank, and there's more twist rates available. Yes- it would take a bit to get them down to size. At least my blank would have a finished OD- one less step. Although, I wonder how much cost difference there is, between machining down the OD to spec, and receiving the "blank" already machined to spec... ANYHOO, Going back to everyone's thoughts on slow twist rates- 1-17 is the slowest available, and there's more than a few twist rates between 1-14 and 1-17... Thoughts on whether a slower twist rate than 1-14 is more beneficial? I MAY experiment with longer/heavier cast boolits in the future. I don't want to get TOO crazy, but I'm not afraid to get another mold or two, that are heavier than 100gr.+
Also, thanks sb327- I honestly didn't think to look again at LW's rifle blanks. For some reason, when I looked at their offerings a couple days ago, I didn't see any .308 barrels listed for some reason- which I thought was odd- they offer ".308" in AIRGUN, but not PB?! I guess it was my fault, as I missed them somehow.
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There's also a 154 gr slug that I'm interested in as well, .924" OAL...