22 hornet keyholing

[mksteyn]

I have been using my .22 hornet BSA hunter for a while with open sights. I recently fitted a scope to it and fired a couple of groups with it that were quite tight then it started to keyhole the bullets on the target. The crown looks ok and the rifling is still good. it is an old rifle but it was literaly three shots in the group were punching through and the fourth shot keyholed.

 

[451 Detonics]

Reloads and factory ammo both are capable of having a bad batch of bullets. If a change in ammo does not solve the problem I would really have to suspect the crown or muzzle. Wear on either can cause key holes.

 

[Walkalong]

Was it good stiff target paper with a solid cardboard backing? Flimsy paper can make it look like the bullet is tumbling.

Welcome to THR

 

[mksteyn]

it was normal printing paper, stuck onto a cardboard backing. it just started so suddenly. this is the concern.

 

[Tim the student]

I'm assuming that you shot more after than the fourth shot that keyholed. Did you?

If not, I'd give it a go again, and see what happens.

 

[mksteyn]

Yes I shot about 6 shots. all did the same so i changed the heads to heavier heads, with the same results.

 

[451 Detonics]

I had a competition revolver go from shooting 1 inch 50 yards groups to keyholing every other round in a single cylinder full. No visible reason for this to happen but under high magnification the was a minute crack in the forcing cone. Point is it take very little, often invisible to the naked eye damage, to cause a problem. I would start thinking about a recrown if there is no other damage to the bore. Also try using a bore scope to check to make sure something didn't create a bulge in the barrel. a spider can leave a small eggsack in a bore that creates an almost invisible bulge.

 

[mksteyn]

thanks will have to take it to a gun smith if i can find one here and see if they could do something. any one have any idea what a new barrel would cost?

 

[451 Detonics]

A lot more than having the crown re-cut...lol. If a new barrel is an option I would try something else first. 21 3/4 inch is the magic number when it come to accuracy, I would have the barrel cut to that length and a target crown done and try that first.
Read this old article http://www.angelfire.com/ma3/max357/houston.html and give it some thought...

 

[Art Eatman]

Determining if there is a problem at the crown is easy: Visual inspection. Shouldn't be any dings or wear showing. But, if three shots were okay and then the problem began, I'd suspect some other cause.

I don't know if a dirty barrel could cause it, but maybe some flaw in the bullets might do it. But, there again, using different ammo didn't improve the results.

I guess I'd start with a good cleaning of the barrel and then go with some brand-new factory ammo. If no solution, then, off to a gunsmith.

 

[rcmodel]

I'd try cleaning it with a good Copper Solvent before I did anything else.
It could just be a bad case of jacket fouling reached the critical point while you were shooting that day.

Also, you made no mention of what weight or type of bullet you were shooting.
If you were reloading a heavier then normal bullet weight, or perhaps a longer plastic tip bullet?
The standard 1/14 or 1/16 rifling twist in your rifle is too slow to stabilize it.

rc

 

[NCsmitty]

+1 for cleaning.

A rifle generally will not transition from tight groups to keyholing in a session at the bench because of barrel wear or a bad crown. A fouled barrel is the likely cause, and as recommended, a good soaking with a quality solvent should solve the problem. It certainly is the cheapest method to try first.



NCsmitty

 

[stchman]

IIRC, when a bullet keyholes that means that the bullet is too heavy for the barrel's rifling to stabilize with its twist.

What is your .22 Hornet rifle barrel twist and what grain slug are you using.

In the lower grain bullets (35-40) a 1:16 twist is just the ticket as that is about the same weight as a .22LR bullet.

 

[alsaqr]

Many .22 Hornet guns will not stabilize a bullet over 50 grains in weight.

 

[mksteyn]

I was using 45grain softs. the barrel stamp says 45 grain. the second lot of ammo was 55 grain sierra varmenters. I've got some original winchester ammo that i will try this weekend. i hope that and a good cleaning of the barrel will help.

 

[FlyinBryan]

im going to say get after it with a really good copper solvent.

thats a fast little bugger and it wouldnt take long to really foul one up once gilding metal starts form in a really fast barrel, it multiplies like ebola.

ive found that not all good bore cleaners are really good copper solvents.

take a penny and put a drop of any given solvent on it. if it turns the penny green in just a matter of hours, its a pretty good copper solvent. if it turns it green AND its still wet after a week, chances are its a really good copper solvent.

(as stated in "the m1 garand owners guide" by a well known high power guru)

 

[mksteyn]

thanks I will try that and get back to you.

 

[x_wrench]

copper build up in the barrel was my first thought. but that seldome comes on all of a sudden. my second thought was the target tearing. i have had that happen a lot, especially if there is a cross wind. before you spend money on a smith, give her a good cleaning with copper solvent (like sweet's 7.62) and try targets made from cardboard or card stock.

 

[mksteyn]

Good day to you all. Thank you for the advise concerning my .22 hornet. I have taken my time and cleaned it properly. I shot with it on the weekend and it has stopped key holing. Now I need to establish how many shots it will take to foul it to the point of keyholing again. Thanks again.

 

[Art Eatman]

Crossed fingers. Let us know if or when you encounter the problem again. It would be a good clue for other Hornet users.