jkhan .22 and 30g bbt update

[oneshot61]

Had a chance to sneak in a few rounds today with my jkhan noblesse .22. I had previously shot the 30g bbt sized at 217 nose and 219 rear drive band. Ok accuracy to 50 yards but I felt they could definitely do better. I ordered some sizing dies from noe for my .25 and one for the .22 in 216.. sounds a bit small I know. The lothar walther is 215 lands 221 groves... but is also chocked. So I sized down a few and ran down to the range. Definitely tighter groups, on par with my shooting the 18 jsb... with the open reticle, not a scope.
 The picture below is 5 shots, three in the same hole...winds, nnw @ 11 mph with higher gusts, open reticle. When I can, I'll get a .217 sizing die and try that also, but I must say I am very encouraged with the new results. That group is a bit less than the size of  a dime.

[Prouzy]

Thats looks nice!

[K.O.]

Had to go look at your prior thread to find what sight you meant...

So is that your best group or a repeatable group ( hope it is the second) if so sweet...

I also had to go make sure but you are sending these at about 900 fps right?

 So anyways once I saw the NOE iteration of the BBT I thought these really look right for air rifles  relying on the nose and rear band rather than multiple bands more on the body and then Bob drew  up the lights... I was like now those with less fpe will be able send them... just for fun and just to see if they stabilized I sent them out of a 18" disco barreled 20 fpe 13xxish pumper...  standing side rest got me .75"-1" groups at 40 and 50 yards at about 550 fps... rainbow trajectory but no signs of yaw...

Not really the rounds strong suit cause at that velocity imo you are better off with 14g-20g...  but it did show that they should do well in a Disco up to the fpe the shallow rifling will handle...

I keep having to put off getting a few .22 barrels set up for my .25 Mrod... but am exited to see them doing well in a L.W. barrel at velocity...

I feel these will make an excellent hunting round... I used the estimated B.C. for the BBT(.0634) and Chairgun's  B.C. for the 18g JSB... I set the velocity for the BBT at 900 fps and the velocity for the JSB at 950 (if it can send 30g at 900 it can hit 950 with 18g easily)... I then used a 11mph wind from 315*...  graphs bellow

so then used compare mode to generate some graphs that shows why though the trajectory is close the BBT is potentially a much better hunting round if your rifle is accurate with them...  wonder how far out the will do well to... on a calm day...

[oneshot61]

It is repeatable. I shot some at 35 yards and then at 50, even with the wind kicking... and I did wait on the best case scenario with the wind before shooting, its a keeper. I was really not expecting them to group that well having sized them down that far, but it was a guess as to what would grab the grooves and still make it through the choke.
  My friend Rick that made these for me, he has a disco with stock barrel that will hit about 50 ft lbs and it shoots these about what your getting at 45 yards. I think the disco barrels typically run a bit big and he didn't size his at all, just shot as cast.
 Wow.. thanks for printing those charts. Really puts the bbt capability into perspective. Backing down the power and shooting at around 900, I get a nice low es shot string to start. I can definitely crank them up, somewhere in the 940-945 range. I'm going to port this one to 4.7 mm and get the power curve a bit lower in the pressure range and should get a nice power tune with the bbt. I am hopeful to be able to get some more shooting time in tomorrow and ill try to stretch them out a bit. I do not have a dedicated scope for this gun and its a real pain to keep switching and resetting scopes. The open reticle is a great, fast acquisition tool for raccoon size to 50 yards around my house.
 I am going to be sizing everything I shoot from now on. It takes the guess work out, and narrows the field of why something may not be shooting at optimum performance. I love these noe sizing dies, and for the price cannot be beat for what they do for accuracy..imo.
 For a reference as I did not have my calipers with me when I shot, there is a pic of the size of the bulls eye, the second pic is 4 parting shots before I left as the wind was getting nuts, two in the bull was 18 jsb, two to the left is the bbt.  The dot on my reticle nearly covers the entire inner circle with no magnification, even though its 2 moa. It does show that I am at this time of shooting, getting equally comparable groups with each.

[K.O.]

P.S.

was low/conservative on the B.C. of the 30g BBT   it has tested out to about .8 or so by multiple folks(and me using trajectory)... so the BBT will actually do better than charted above...

[Wayne52]

I've been hunting with the 217-30-RF cast slugs in HP with the RG mold.  I shoot them as cast from the mold through my Airmax Dominator doing about 800fps and they're 27.5 grain.  Ever since I've been using these slugs for hunting I haven't been shooting anything else except them from the gun and they're much more accurate than I can shoot.  I only use them in unchoked barrels.  They shoot good from my Crosman 150 pistols as well.

[ranchibi]

Excellent groups after resizing those slugs! Good stuff 👍.

[rsterne]

Excellent indeed.... 

Bob