I've been shooting a mile for a few days with mixed results. Today I got a keyhole. It's Jamison factory loads. 419gr. bullet and 131.4 gr. of powder. I pulled 3 apart and weighed the charge .All identical. Chey-Tac white paper leads me to believe this should not happen.I do get about 15% duds. I replace the primer with 215 MM. It's not the reloads. I assumed it unlikely that I got mixed lots of rl-25 in a can of factory. Could the primers be the cause of erratic performance?
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Range Report 408 keyhole
- Thread starter hessian
- Start date
Re: 408 keyhole
Primers do not cause keyholes, instability causes keyholes.
What is the twist rate of the barrel and what is the length of the bullet?
Primers do not cause keyholes, instability causes keyholes.
What is the twist rate of the barrel and what is the length of the bullet?
Re: 408 keyhole
What atmospheric conditions were you shooting in?
What is the MV and the published BC of the projectile?
Can you post a picture of the entire projectile, specifically the tail?
What atmospheric conditions were you shooting in?
What is the MV and the published BC of the projectile?
Can you post a picture of the entire projectile, specifically the tail?
Re: 408 keyhole
72 degrees 40% humidity 2234 ft. DA of 3833ft. 29.99 pressure .No wind, but shooting over a hole about 600m deep.Have not chronographed. Published M. V at 2950fps BC is about .95. Some say 1.0 Consulted gunsmith who said it's dirty barrel. Will borescope soon as possible. Picture of bullet at "Chey-Tac LLC"
72 degrees 40% humidity 2234 ft. DA of 3833ft. 29.99 pressure .No wind, but shooting over a hole about 600m deep.Have not chronographed. Published M. V at 2950fps BC is about .95. Some say 1.0 Consulted gunsmith who said it's dirty barrel. Will borescope soon as possible. Picture of bullet at "Chey-Tac LLC"
Re: 408 keyhole
I'm probably way off on this, but it's a thought and something I have experienced before.
I was shooting at 850 with my 7mmRM and was getting keyholes in my target. As it turns out, I was actually hitting low and ricocheting into the target... Again, just a thought.
I'm probably way off on this, but it's a thought and something I have experienced before.
I was shooting at 850 with my 7mmRM and was getting keyholes in my target. As it turns out, I was actually hitting low and ricocheting into the target... Again, just a thought.
Re: 408 keyhole
1236- Thanks. I don't trust the BC's that CheyTac published and their white paper on "controlled spin stability" leaves a lot to be desired.
I was looking to see what kind of inputs you're using, if you were tracking the atmospheric info, etc. and since you are and the tail of that bullet isn't totally jacked up I'm apt to agree with SavageLapua. I've seen a lot of long targets take skips and be counted as a "hit"
At a mile, if you're off by 50fps or a 3-5% in your BC it's entirely possible to have a skip only a few feet in front that looks like a keyholed impact.
1236- Thanks. I don't trust the BC's that CheyTac published and their white paper on "controlled spin stability" leaves a lot to be desired.
I was looking to see what kind of inputs you're using, if you were tracking the atmospheric info, etc. and since you are and the tail of that bullet isn't totally jacked up I'm apt to agree with SavageLapua. I've seen a lot of long targets take skips and be counted as a "hit"
At a mile, if you're off by 50fps or a 3-5% in your BC it's entirely possible to have a skip only a few feet in front that looks like a keyholed impact.
Re: 408 keyhole
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SavageLapua</div><div class="ubbcode-body">I'm probably way off on this, but it's a thought and something I have experienced before.
I was shooting at 850 with my 7mmRM and was getting keyholes in my target. As it turns out, I was actually hitting low and ricocheting into the target... Again, just a thought.</div></div>
This was my exact thought also. I think you skipped a round.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SavageLapua</div><div class="ubbcode-body">I'm probably way off on this, but it's a thought and something I have experienced before.
I was shooting at 850 with my 7mmRM and was getting keyholes in my target. As it turns out, I was actually hitting low and ricocheting into the target... Again, just a thought.</div></div>
This was my exact thought also. I think you skipped a round.
Re: 408 keyhole
I thought it possible since I have bounced a few 6.5's at 1km, but i always got dirt marks on target too. I did see low dirt impact geyser. You are probably correct. The bore is clean and I'm going out now to try again. Thanks for your responses, Art
I thought it possible since I have bounced a few 6.5's at 1km, but i always got dirt marks on target too. I did see low dirt impact geyser. You are probably correct. The bore is clean and I'm going out now to try again. Thanks for your responses, Art
