GTA
All Springer/NP/PCP Air Gun Discussion General => Projectiles => Boolit and Pellet Casting => Topic started by: Bob Pratl on August 02, 2019, 07:42:05 AM
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As Wayne stated, this slug was hard to chamber in the Liberty which I also found. The smallest .22 sizing bushing that I had was a .217 so after sizing I found it was still hard to chamber so I ordered a .216 NOE bushing which just received and resized a few to test. They are still hard to chamber so I decided to slug the barrel which turned out to be .2135-.2140. So now I just ordered a .215 NOE bushing which should have ordered with the .216.
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My experience is that when sized to fit, the slug looses its drive bands and is making full contact with the barrel, way to much resistance. I just gave up and get swaged slugs from Stephan on Ebay LOL
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Bob now I'll know which ones to order for .22. Those slugs seem to load right up in all my Crosmans pretty good. They chamber really good in my Prod too. When I put my next order in at NOE I'll order the .215, .216 & .217 bushing, that way I should be able to size them for about any .22 airgun. I think for the .25 slugs I'll order three sizes under as well.
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I noticed early on the stiff loading of the 14.3 CHP's on the Liberties. Stephen lists his slugs as .217, the two batches I have are both .215 (.2148 - .2151) nominal and work really well both loading and shooting. I suspect the 5.5mm (0.216535in) has been on the under size in the container load we have been experiencing.
The two batches of slugs I have from other vendors are indeed .217" and both load tough and do not shoot well.
With only 3 rifles on hand to note, I don't intend to imply anything definitive. Also as we all know the next shipment may have vastly different barrels. (Not limited to China imports, Crosman has kept me guessing many a time)
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Bob now I'll know which ones to order for .22. Those slugs seem to load right up in all my Crosmans pretty good. They chamber really good in my Prod too. When I put my next order in at NOE I'll order the .215, .216 & .217 bushing, that way I should be able to size them for about any .22 airgun. I think for the .25 slugs I'll order three sizes under as well.
Wayne, excellent decision, you will never regret it. NOE sizer system is so nice and exact. I have been checking the sized slugs with a very precision anvil type mike and they came out to .21602"
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Liberty's have a tight almost undersized barrels...
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My experience is that when sized to fit, the slug looses its drive bands and is making full contact with the barrel, way to much resistance. I just gave up and get swaged slugs from Stephan on Ebay LOL
Hmm are you using the .217/.219 mold or the .220/.222 mold..?
The body of the .217 from my .217 mold is at .212 and should be fine... I have a full sizing set from .215 to .224... even sizing to .215 did not wipe out the bands on mine...
Right now with the .217 mold and my AT 44 long the only thing that works is sizing to .216 and knurling... they run down the side of the barrel which is .215 land height and almost .220 groove...
I will be trying some from my .220/.222 mold soon and feel they may do better because the body of the round from that mold is .214 plus a very small smidge...maybe .2142 or so... so even on those the bands will still be about .0015 or so proud of the body when sized to .216...
I will be ordering a few more sizing inserts in order to open them up to create some in between sizes... may make a difference in some of the choked barrels to have the round custom... to say .2165 or .217 or .2175 or so... My .25 Mrod only likes the 40g BBT at .2495 and .250... anything else groups open up badly...
My .22 Maximus barrel seems pretty tight also...but I forgot exactly what it slugged to...but was about 216 maybe a touch tighter...
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It is a shame there is no standardization on airgun barrel land and groove diameters.... LW list their barrels as 0.215" land and 0.221" groove.... which is IMO on the loose side.... They are smaller at the choke, of course.... When Sean Pero and I consulted with Mike on the TJ's pellet barrel we suggested 0.213" land and 0.217" groove.... I understand that the MMHF barrels are the tightest of all, at about 0.213" groove.... Pretty hard to make a mould that will allow bullets to be made over an 0.008" variation in diameter.... ::)
Bob
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.217 sized down to .215. T then pushed it through my barrel and had rifling marks all the way along the bullet, very tight fit.
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If the land diameter is less than 0.212" then the center section would be engraved by the rifling.... I would think that would also happen with the MMHF barrels.... It must be impossible to chamber or shoot the NSA slugs as well, as them are swaged at 0.217"....
Bob