key holes

[oldrookie]

I was at the range yesterday shooting my sandby load of 300g xtp and 90g of 777 loose. I noticed first few shots did not hit the paper with a crisp hole. I assume, this is what I have read on here as described as a key hole. What causes the bullet to do this? Didn't do it on all shots but this is the first experience for me.

[MLKeith]

You indicated that it was the first few shots. Is there a possibility that the barrel was not cleaned completely of storing oil? Usually a keyhole is the result of too light a load for the bullet combination. Maybe the powder was messed up by existing oil?? Although I usually find that sabot loads are a lot less subject to light load keyhole syndrome.

[oldrookie]

MLKeith, this has been my "goto" load. I swabbed the barrel and then fouled it like I normally do. The temps and humidity are starting to climb here in Indiana. Would that make a difference? Maybe 90g of powder is on the low in for the 300g hornady. I'll be back out tomorrow, should it happen again and you think its under powered, I'll up it to 95g or even 100g. Just didn't think I needed it before. Thanks for your help!

[gleason.chapman]

ORIGINAL: oldrookie

I was at the range yesterday shooting my sandby load of 300g xtp and 90g of 777 loose. I noticed first few shots did not hit the paper with a crisp hole. I assume, this is what I have read on here as described as a key hole. What causes the bullet to do this? Didn't do it on all shots but this is the first experience for me.

Old rookie,
I noticed one of my shot this AM also was Kinda long like it was keyholed or sideways. I looked at it carefully when I got closer to he target and it was fine. It was about 75 degrees here in NO. Va. this am, perfect for shooting. I think the crisp hole are in new cardboard, once you shoot it out it is no backing behind the paper targets. That is my theory.
Chap Gleason

[cayugad]

I was shooting loads today from 70 - 110 grains of two different powders. I was shooting 250 grain Shockwaves and 200 grain Hornady XTP's. Not a single keyhole no matter what the powder charge.

I have noticed more keyholes in hot weather then cold weather. The reason for them I have no idea. Maybe the sabot and projectile are more prone to sticking together longer which would cause an erratic flight.

[oldrookie]

cayugad....do you think its a matter of being undercharged at highter temps/humidity? When I set this load up it was cooler, not cold but certainly not near 90 degrees and 80% humidity. If I need to add 5-10g in warmer temps....no big deal. I just had never seen this before and am learning. What do you think?

[MLKeith]

I think your charge is plenty if the powder is good. The point I was trying to make is that there is a possiblilty that the first few shots might have had the powder contaminated with storing oils. I think 90 gr of T7 is plenty for the 300gr. bullets. The comment about the sabot staying with the bullet too long is interesting. Not sure how that could happen but interesting. I only had some powerbelts keyhole (one 348gr. that went through and elk sideways without even losing the plastic aero-tip when found in the far side skin). That was with too low a charge of a the old goex ascorbic acid based powder that was pretty poor. That was the explanation from CVA. Once the powder was changed to a better one and the charge upped from 80gr. to 90 gr. all the bullets flew straight.

[frontier gander]

same here. when i was shooting the 225 powerbelts in my 45, i'd find the plastic skirt by the target. Upped my charge to 80 grains triple 7 and the problem was solved.

[cayugad]

cayugad....do you think its a matter of being undercharged at highter temps/humidity? When I set this load up it was cooler, not cold but certainly not near 90 degrees and 80% humidity. If I need to add 5-10g in warmer temps....no big deal. I just had never seen this before and am learning. What do you think?

I would hate to say that is the cause. You might try adding 10 grains of powder to the load and see what happens. I would be interested in the results. I had a shockwave once make a "perfect" sideway bullet shape in a paper target. I was shocked it had done that. I went and looked for that photo in my albums, but was not able to locate it. I wanted to see if the powder charge was changed, what the temperature was, and the weather in general.

My comment about the sabot staying with the bullet too long was really based on today's shooting as well. It was 89 degrees today on the range (finally got to 92). I was shooting shockwaves and XTPs. I was shooting Pyrodex RS and APP 2f. I noted a couple things. The barrel of the Knight rifles were veryhot to even touch. The bullets and sabots that were sitting in the sun were so hot, that it was very noticable. Also normally a sabot leaves the projectile after being fired, between 12-25 yards in most cases for me. Today I found the blue 10mm sabots almost 35 yards down range. (I pick up my sabots after each shot because I hate them in my lawn).

My brass powder measure that sits in the tray of the shooting rest was so hot I changed over to a plastic one and put the powder, caps, and projectiles finally on the shelf under the shooting bench. I did not get a key hole though. I just threw that out as a possible cause because my accuracy today was not as good as it was on cooler days. Was it caused by the sabots sticking in flight longer? Could not tell you. I even brought both Knight rifles so I could trade off and let the other cool as I was shooting.

[oldrookie]

Thanks for the info guys....I am constantly learning. By the way, its not super critical, I still took out the bullseye with all 4 shots.they just came in sideways!