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All Springer/NP/PCP Air Gun Discussion General > Air Gun Gate
Getting a NSA .22 to open up better ... a LOT better !
Wayne52:
I'd rather just cast my own slugs but many don't want to, evidently people don't think they're accurate but I agree to disagree. I shot a chipmunk straight on with this hollowpoint BBT from the gun in my signature at about 25 yards, it entered its skull just to the right of it's left eye and settled in the hide next to it's tail. It literally flew back about 2 feet from where it was shot.
DAN 25:
Excellent idea but for folks with a drill press I think it can be improved. Just chuck the modified driver in the drill press and using the depth scale you can get the same deformation every time for a more uniform modification. Just a thought that popped up. Living and shooting in a suburban area I like that pellets lose velocity fast. For me its a safety feature so slugs may be a thing in the future but for now 31 grain H&N Barracudas are the closest thing to slugs I plan on shooting.
DAN 25:
--- Quote from: TF89 on January 19, 2021, 11:59:32 AM ---I’m having some fun with this. The bit I’m using is a 1/8th Philips bit, is that a # 0, no idea? I started thinking if a cross stamp is good, what about two and getting more of a star pattern? For giggles, I made some up, it took a couple of slugs before I started getting it right as you can see from the picture. Do they shoot as accurate as the single cross stamp? I don’t know, yet. It does look like the nose of the slug is more likely to get out of round, so perhaps accuracy is affected. Really thinking to use at closer ranges anyway, they might open faster on smaller less dense targets. That is the thought process behind it anyway. The other down side is that the petals will most likely separate/shear at higher fps, not a good thing, unless the immediate goal is for fast expansion.
The real reason for doing this is because once I got started, just couldn’t stop. :o The picture shows, the single stamped cross and the and also the double stamped slugs and as already mentioned you will see my learning curve. Included in the pic is the Philips bit I’m using. The end results to the slug hp seems to look like what Scott is getting, yet, uncertain.
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If you want more than four flutes you could get small torx driver bit. You might have to sharpen the tip a bit, think of a shallow pencil type tip. It would be easier if you use one of the extended length driver bits. If you mess it up grind it flat and have another go at it. Worst case bring it to a machine shop and they can get the exact profile you want. If you have access to a drill press chuck it up and hold a file against it and get your profile. Get a small triangle file and sharpen the leading edges of the flutes and there ya go.
AppalachianAirgunner:
--- Quote from: Motorhead on January 12, 2021, 07:13:13 PM ---First off not my idea, but taken from a few recent posts about low velocity slugs that mushroom easily. Thank you guys !!
So ... taking a #2 Phillips screw driver tip then dressing each blade web with a dremel tool cut-off wheel, we get each web a tad thinner / sharper.
* Took me 3 tries getting my grinding technique right & having control over equal thinning where it would contact the slugs hollow point making a uniform impression.
Placing a NSA slug on a piece of flat and thick leather, gave three TAP TAP TAP's on the end of driver tip with a small tac hammer so the hollow cavity of slug took on this look.
Once establishing how hard to strike was able to go threw a 375 count of NSA 20.2's in @ 45 minuets. Neurotic YES !!!
AS TO TESTING .... O' yes they now POP open where before was not that impressed :P
Shot from @ 20 yards into 1 gallon jug of water at @ 1040 fps a stock 20.2 HP passed right threw the jug exiting leaving a round hole ... had tried this prior with a few bottles in line to catch the slug. In the past recovered slug was only slightly opened at HP cavity and in no was mushrooming :P
MODIFIED with an X from tool described and shown, slug enters jug and does this !!! POP peeling away to the depth of the HP cavity in a near perfect clover leaf shape. Started as a .22 caliber and opened up to a .380" clover having no measurable weight loss still weighing 20.2 grains.
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Talk about ingenuity! Air rifle dumbdumbs. I imagine the big ores would even effectively use glaser rounds, the hollow headed slugs filled with Teflon shavings a lube. Destroy the soft tissue, leave the bone alone, no pass through.
Motorhead:
For the past 6 months or so been further experimenting shooting modified NSA's ( .22 in particular )
last fall got my hands on one of TROY HAMMERS ( His web name ) prototype TJ's 3 groove barrel.
With just 3 narrow LANDS the bulk of bore contact is GROOVE having as with most slug shooting in air guns, have a very small clearance slug O.D. to Bore Lands I.D. which leads to a little bit of sealing losses.
Ok ... Said, here is something found out that actually has increased the slugs speed @ 15-25 fps and also appears the ES value is running just a tad tighter.
When X scoring the H.P. cavity via hammer Tap Tap, did so on a HARD surface rather than on leather or plastic ???
RESULT is the Cup Base of the slug also slightly flattens on the outer most diameter. Measured looks to be @ .001" or so.
What we get in this case is a .217 slug with very small Flair or Bulge right at the slugs base. It loads and shoots like a .217' but barrel seals as if a .218" or so ;)
Picture of slug on side was loaded, then pushed back out from muzzle using a cleaning rod. Hard to get picture sharp enough, but you can see the shine of Groove contact right at base area.
Picture of Slug bottoms clearly shows the very slight widening of dish outer most edge.
Just sharing & your mileage may vary 8)
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