Why bother?? -Y
Quote from: Yogi on March 08, 2023, 05:39:58 AMWhy bother?? -Y1. EMS adds a lot of good improvements.2. This barrel (or one like it) should come from the factory for the heavy (e.g. JSB Monster and JSB Beast) .177 pellets: https://www.lothar-walther.com/gun-barrel-blanks/airgun-barrels/polygon-profile-with-choke/1569/airgun-blank-choked-twist-36.177-air-polygon-od.63-l-23.82-precision-rifle-steel-tube(See attachment below for specs)Then, of course, a factory tuned spring and total piston weight (piston, guide, top hat, spring) to make it shoot more efficiently with heavy pellets and thus soft for it's given power. If necessary, print clearly on barrel to avoid lightweight pellets.The same can be done for the .177 slug configuration which I suspect would use the same spring and piston weight as the heavy pellet optimized .177. However, the barrel would different by using a faster twist with no choke and groove diameter matched very closely to the diameter of the .177 slug which are typically sized .178".A factory smoothbore for bird shot, optimized diabolo pellets and "shotgun type" slugs could also be made interesting as well. For people that like the common weight pellets there is always the standard .177 configuration (barrel, spring, piston weight) that could be used.
Quote from: UnderPressure on March 08, 2023, 06:23:36 AMQuote from: Yogi on March 08, 2023, 05:39:58 AMWhy bother?? -Y1. EMS adds a lot of good improvements.2. This barrel (or one like it) should come from the factory for the heavy (e.g. JSB Monster and JSB Beast) .177 pellets: https://www.lothar-walther.com/gun-barrel-blanks/airgun-barrels/polygon-profile-with-choke/1569/airgun-blank-choked-twist-36.177-air-polygon-od.63-l-23.82-precision-rifle-steel-tube(See attachment below for specs)Then, of course, a factory tuned spring and total piston weight (piston, guide, top hat, spring) to make it shoot more efficiently with heavy pellets and thus soft for it's given power. If necessary, print clearly on barrel to avoid lightweight pellets.The same can be done for the .177 slug configuration which I suspect would use the same spring and piston weight as the heavy pellet optimized .177. However, the barrel would different by using a faster twist with no choke and groove diameter matched very closely to the diameter of the .177 slug which are typically sized .178".A factory smoothbore for bird shot, optimized diabolo pellets and "shotgun type" slugs could also be made interesting as well. For people that like the common weight pellets there is always the standard .177 configuration (barrel, spring, piston weight) that could be used.My PCP buddies say .177 slugs are a joke! Even .22 slugs. They say you need to volume of a .25 to push that heavy thing out.Everybody knows that the Diana 350 is best in .22, so why go on and on about .177? -Y
Now, to slugs:Their natural place is a PCP.For piston guns, the Diabolo shaped pellet has simply too many advantages.Specialty slugs could be developed, but then they would not fit as well into the PCP world.
While I agree the Diabolo Shape has many advantages, the flare stabilization happens by far the best on the long pellets. In fact, Tom Gaylord did a test (linked below) one decade ago with average weight pellets (which benefit less from flare stabilization than long pellets) and they did better with a 1 in 16" twist than a 1 in 22" twist.https://www.thefreelibrary.com/A+new+spin+on+air+rifle+twist+rates%3A+most+all+airguns+use+a+twist...-a0344213054Moving on to slugs JSB makes a 10.03 grain .177 slug:https://www.airgundepot.com/jsb-knockout-slugs-177-cal-10.03-gr-500-ct.htmlThis is light enough to use even in a non magnum gun like the Diana 34 EMS.....so I don't see why 10 grain and heavier .177 slugs should be excluded from more powerful springers. The biggest problem I see with combining slugs and springers is how Lothar Walther sizes their .177 and .217 airgun barrels. For slugs the barrel ideally should be sized .0005" tight (In other words the slug should be sized .0005" over groove diameter). However, Lothar Walther sizes their conventional .177 barrels with a .182" groove diameter. When matched with a .177 slug sized .178 that is going to result in the slug fitting .004" too loose. The Polygonal Lothar Walther .177 barrel is better at .181" groove diameter but it would still be .003" loose when paired with a .177 slug sized .178 (rather than the ideal of .0005" too tight).Other barrel makers don't oversize their Airgun barrels like Lothar Walther does.So the problem I see combining springers and slugs is one of making sure the barrel is sized right. That and making sure it has no choke.No Specialty slugs required.
Quote from: UnderPressure on March 09, 2023, 05:21:30 PMWhile I agree the Diabolo Shape has many advantages, the flare stabilization happens by far the best on the long pellets. In fact, Tom Gaylord did a test (linked below) one decade ago with average weight pellets (which benefit less from flare stabilization than long pellets) and they did better with a 1 in 16" twist than a 1 in 22" twist.https://www.thefreelibrary.com/A+new+spin+on+air+rifle+twist+rates%3A+most+all+airguns+use+a+twist...-a0344213054Moving on to slugs JSB makes a 10.03 grain .177 slug:https://www.airgundepot.com/jsb-knockout-slugs-177-cal-10.03-gr-500-ct.htmlThis is light enough to use even in a non magnum gun like the Diana 34 EMS.....so I don't see why 10 grain and heavier .177 slugs should be excluded from more powerful springers. The biggest problem I see with combining slugs and springers is how Lothar Walther sizes their .177 and .217 airgun barrels. For slugs the barrel ideally should be sized .0005" tight (In other words the slug should be sized .0005" over groove diameter). However, Lothar Walther sizes their conventional .177 barrels with a .182" groove diameter. When matched with a .177 slug sized .178 that is going to result in the slug fitting .004" too loose. The Polygonal Lothar Walther .177 barrel is better at .181" groove diameter but it would still be .003" loose when paired with a .177 slug sized .178 (rather than the ideal of .0005" too tight).Other barrel makers don't oversize their Airgun barrels like Lothar Walther does.So the problem I see combining springers and slugs is one of making sure the barrel is sized right. That and making sure it has no choke.No Specialty slugs required.I don't think you fully understand how a pellet fits into a rifling.Tom's tests were about rifling TWIST, he did NOT compare different pellet lengths, just rifling twists.Given the wide array of available pellets, to do an extensive test would be a community effort (which has been done, BTW, in the UK).Under Tom's tests, the best twist was the standard twist used by almost all makers (1 in 16")L-W has produced more championship titles than any other barrel maker. I have had the pleasure to work with Frank, personally, on a few projects, one of them even contained non-rifled barrels (smoothbore), LOL!.I have also had L-W make custom barrels for custom guns, we have explored the twist, the dimensions, and the tolerances, so we know a bit about what we are talking.I don't think I am revealing any trade secrets when I tell you that the barrels for pellets are made with the specific intention of having the head ride the lands, while the skirt seals the grooves.THAT defines the internal dimensions of barrels. And that defines what you term "loose" barrels.(Snip)AFAIK, the JSB KO 0.177" is "coming soon" and therefore, for the time being, made of "unobtainium". I have contacted Predator, and will see exactly what they are when they get here.
You want energy on target use a larger caliber. Reliable hunters who hunt with .177 do with shot placement not energy on target. Maybe you should practice precision shooting. !/2 inch groups of less. Anyway, since springers are a dying breed, all you ideas are just "pie in the sky". -Y
Or better yet, get 500 people to sign up for one, get them to pay in advance, then go to Germany with the cash in hand and ask them to make it. Money talks, BS walks... -Y
Quote from: Yogi on March 11, 2023, 07:48:40 AMOr better yet, get 500 people to sign up for one, get them to pay in advance, then go to Germany with the cash in hand and ask them to make it. Money talks, BS walks... -YJSB Knockout slugs are now about the same price as JSB pellets of the same weight. People want to slugs....and now price is no longer an obstacle. The slug barrels will come no doubt about that. In fact, transitioning to slug barrels was no doubt part of the reason EMS was developed.
Quote from: UnderPressure on March 11, 2023, 09:53:01 PMQuote from: Yogi on March 11, 2023, 07:48:40 AMOr better yet, get 500 people to sign up for one, get them to pay in advance, then go to Germany with the cash in hand and ask them to make it. Money talks, BS walks... -YJSB Knockout slugs are now about the same price as JSB pellets of the same weight. People want to slugs....and now price is no longer an obstacle. The slug barrels will come no doubt about that. In fact, transitioning to slug barrels was no doubt part of the reason EMS was developed.Same price for 350 vs 500 in a pellet tin. PS all the sub-MOA shooters, at 200 yards at the range say that you need minimum of 925+fps to stabilise slugs. Yes, they are shooting .25 cal FX guns.