Okay further problems with my supposedly Sportco Martini.

Background
I bought it from the cadet martini guy always at the Las Vegas gun show.  The pilot that flies back and forth from Aussie land and imports these things. The gun has a Sportco barrel on it, .222 Rimmed. So I assumed that it was a Sportco re-barrel factory so to speak from Sportco.

From my last post, I could not get the gun to close on a new .222 rimmed shell.  I alter a .38 special shell by about .004 and it would close.  It appears the barrel was turned in a bit far.   
Funny, who could have shot it that way?  Could it have never been fired?
I shaved .003 off of the breach face and it closes hard on a shell.  I noticed the firing pin had not been bushed.  DeHass say they needed to be bushed.  I bushed my last one, but I have read of others who did not bush them.

I went to my range and fired 4 shells with it.  1 shot at 50 yards didn't hit the 32 x 40 target.  3 shots at 25 yards printed 20" pattern.  The bullets are key-holing.

The breach locks up from the primer flowing around the firing pin. had to stop at the 4th shot as I could not get the gun open again.

My load was H322 with 36 grain Barnes Varmint grenades.  Just above starting loads in the hornady manual.  The bullet has been very accurate in my .223's

I am guessing it is a parts gun with a shot out barrel hastily put on the gun.  Any other opinions or thought?  So it appears I have been screwed either by Mr Martini Airplane piolet or someone who sold it to him.  Could this be something other that what it appears?

I am capable of bushing the firing pin, but I think I am going to have to re-bore the barrel.  I don't have a bore scope, but with a light, the bore doesn't look bad.  Before I re-bore, any thoughts on the key-holing?

If I do re-bore any recommendations: some I have thought of:
25-20 WCF (i have brass and dies from a gun long ago stolen)
.25/35 for fun or.25/35 AI?
7-30 Waters.  A very useful caliber for hunting, although I have plenty of hunting guns.
30/30 Kinda dull.

Please provide any and all comments and lambasting 

Jerry

PS I did get the gun for a good price maybe what the action is worth and the 1st martini I bought from the guy was a far deal too

Check the Twist. .222 Caliber Rifles are showing up with all kinds of twist for heavy to light weight bullets. Sounds like this one does not like Light. I tried some Sixty Gr. bullets in a M1885 built in the early 50s. Like you I could not hit anything at 200 Yds. And nothing that even looked like a group at 25 Yds.
In fact the bullets were going in sideways at 25 Yds. The Barrel looks great inside. So I believe it just needs some bullets in the 50 Gr. Range. HTH Regards, FITZ.

Slugging the bore is my next step while I bush the firing pin.  I guess I should check the twist rate.

The 36 gr varmint grenades are really quite long for their wt. so I don't think the twist is too fast, I guess it could be too slow for these bullets.

I haven't run across this within other .22 barnes.  I have some 30 grain varmint grenades made specifically for the .22 hornet.  I might try them.

Unfortunately, I need the unleaded here in the communist state of CA.

Keep the input coming I appreciate it..... I have quite a few .22 hornets and .223's so the thought of something else is still a possibility.

I have another model 12 BSA .22 LR target gun that I may convert to some target type caliber, so this one could be a hunter.

Funny, I just love these little guys.

Jerry