Not being familiar with the Pro Hunter slugs, I went to their site and looked a bit. What I found was slugs listed by cal. and weight. I must have missed sizes.
You see, they have to be no more than .0003" over the bore to work reasonably well. In most of my slug guns in the smaller cal's, they work best at .0001" under to .0001" over for beat accuracy. You simply cannot select a cal. and expect it to work.
It isn't that the barrels are slug fussy so much as folks are trying to shoot slugs without selecting or sizing to the bore or choke with the additional issue as to not understanding that the twist requirements are not weight, but rather the length of the projectile.
I would suggest going to a site such as the Colby Twist Calculator to see how close a given projectiles requirements in twist are to the slugs you are contemplating trying. Most AG barrels are to fast for most of the slugs in .25 for instance.
No, FX barrels are not fussy at all. Nick of NSA, maker of mighty fine slugs for airguns understands this, and has worked with FX to develop his slugs to be very accurate in them. First the correct dia. for the bores, and secondly, the overall length to best take advantage of the twist rates.
His latest slug in .25is almost identical to one I cast, being a 29 gr slug with HP. Mine is .29.3 grains sized to .2510" and is extremely accurate in my L/W barrel. However, being a 1-17" twist, it does start to become unstable a longer ranges. It is simply over spun. the FX barrel is however, 1-20" twist and does not suffer this shortcoming.
An excellent example of this is my .257 test. The .257 is shooting 80 to 110 gr. bullets like lasers. The 88 Gr. spire point will group 1/4" to under 1/2" at 100" all day long. I tried the 50 gr slugs, and it starts the death spiral at apx. 66-65 yards. this is a 1-14 TJ's Barrel. When I switch to a 1-17 barrel, it does not. Two different barrels twist rates, give widely different results with different length bullets. If needed, I will measure the oal of the bullets.
Another good example is the .177. I only have knowledge of the .172, but in this case, same same Like most typical AG barrels, they are old tried adn kinda true 1-16 to 1in 17 twist. this works fairly well in .177. Ever notice in airguns, all barrels are the near same twist regardless of cal.? This comes from the distant past, long before the high performance AG's we enjoy today. The AG industry has ignored what the PB world discovered a log-long time ago. Different twist for different projectiles. They are standardized. The AG world has resisted standardation. In this case for instance, for slugs, the .172 requires a 1 in 9" twist. Unheard of in AG barrels.
Yes, I am aware the .172 is not .177. But neither is the bore of a.177 really a .177. so it is a mute point. A .22 AG bore is no where near a .22 cal at all. Usually a .216 to .219. Another case of no standardization. It drives me nuts. But exactly why simply buying a slug titled as what you think your barrel is cant work unless you are extremely lucky. If you are that lucky often, it's time to play the lottery, or head to Vegas. LOL I keep a good supply of bullet sizers for this reason, in order to size exactly to my barrels. I don't depend on blind luck. ;<)
Disclaimer: My slugs are my personal use slugs for both target, hunting and continued testing. They are not sold to the public. I Cast for .172, .223, .25 and .257.
KnifeMaker
Knife
You see, they have to be no more than .0003" over the bore to work reasonably well. In most of my slug guns in the smaller cal's, they work best at .0001" under to .0001" over for beat accuracy. You simply cannot select a cal. and expect it to work.
It isn't that the barrels are slug fussy so much as folks are trying to shoot slugs without selecting or sizing to the bore or choke with the additional issue as to not understanding that the twist requirements are not weight, but rather the length of the projectile.
I would suggest going to a site such as the Colby Twist Calculator to see how close a given projectiles requirements in twist are to the slugs you are contemplating trying. Most AG barrels are to fast for most of the slugs in .25 for instance.
No, FX barrels are not fussy at all. Nick of NSA, maker of mighty fine slugs for airguns understands this, and has worked with FX to develop his slugs to be very accurate in them. First the correct dia. for the bores, and secondly, the overall length to best take advantage of the twist rates.
His latest slug in .25is almost identical to one I cast, being a 29 gr slug with HP. Mine is .29.3 grains sized to .2510" and is extremely accurate in my L/W barrel. However, being a 1-17" twist, it does start to become unstable a longer ranges. It is simply over spun. the FX barrel is however, 1-20" twist and does not suffer this shortcoming.
An excellent example of this is my .257 test. The .257 is shooting 80 to 110 gr. bullets like lasers. The 88 Gr. spire point will group 1/4" to under 1/2" at 100" all day long. I tried the 50 gr slugs, and it starts the death spiral at apx. 66-65 yards. this is a 1-14 TJ's Barrel. When I switch to a 1-17 barrel, it does not. Two different barrels twist rates, give widely different results with different length bullets. If needed, I will measure the oal of the bullets.
Another good example is the .177. I only have knowledge of the .172, but in this case, same same Like most typical AG barrels, they are old tried adn kinda true 1-16 to 1in 17 twist. this works fairly well in .177. Ever notice in airguns, all barrels are the near same twist regardless of cal.? This comes from the distant past, long before the high performance AG's we enjoy today. The AG industry has ignored what the PB world discovered a log-long time ago. Different twist for different projectiles. They are standardized. The AG world has resisted standardation. In this case for instance, for slugs, the .172 requires a 1 in 9" twist. Unheard of in AG barrels.
Yes, I am aware the .172 is not .177. But neither is the bore of a.177 really a .177. so it is a mute point. A .22 AG bore is no where near a .22 cal at all. Usually a .216 to .219. Another case of no standardization. It drives me nuts. But exactly why simply buying a slug titled as what you think your barrel is cant work unless you are extremely lucky. If you are that lucky often, it's time to play the lottery, or head to Vegas. LOL I keep a good supply of bullet sizers for this reason, in order to size exactly to my barrels. I don't depend on blind luck. ;<)
Disclaimer: My slugs are my personal use slugs for both target, hunting and continued testing. They are not sold to the public. I Cast for .172, .223, .25 and .257.
KnifeMaker
Knife
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