keyholing question

[gregc]

keyholing question

hey all the best to everyone in the forthcoming year.

so i have a question regarding keyholing. was out to the range today shooting an enfield #5 as i put a new scope on it. couldn't get the rifle to group at all at 100 yards and thought the scope, a nikon monarch, was buggered up as the turrets wouldn't move enough to get bore sighted. so i reversed the rings and while the scope was able to be bore sighted, i didn't have a single hit on the target at 100 yards. the enfield has shot fine before so this was a bit perplexing. in moving down to 25 yards, all of the shots were keyholing in about a 10 inch circle with the target showing the bullets where hitting the target fully lengthwise

i was shooting 180gn cast with an ed harris recommended cast load and had powdercoated the projectiles after resizing them to .313 and didn't resize them after. could the powdercoating have made the projectiles too hard to engage in the rifling, thus causing them to keyhole. i have used this combination of powder/projectiles in other 303s without any issues and the only variable that has changed is the powdercoating.

at any rate, will be pulling the powdercoated projectiles and replacing them with lee allox lubed ones sized to .313 and seeing if these group any better.

could anyone offer further suggestions as to why these powdercoated bullets keyholed like this? thanks

 

[RifleDude]

Load too fast for cast bullets?

 

[Frost Cracked]

I have keyholing issues in one of my 303s with cast bullets. Have you taken a land/grove measurement of your barrel? A lot of enfields, especially wartime production ones, have measurably different bore dimensions as tolerances were... generous sometimes. There's a noticeable difference between my no1 mk 3 and my no 4 mk 1.

Just a thought.

 

[purple]

Keyholing is normally caused by badly eroded rifling which is unable to stabilize the bullet. We used to see this with badly worn machinegun barrels. A 10 inch grouping at 25 yds is pretty extreme. I'd try some factory ammo or handloads with 180gr bullets and see what happens.