Factory loads OK, handloads keyhole?

[SpeedGoatShooter37]

Hello all,
I've been working up loads for my 22-250. I've got a factory load that is shooting bullet that I am handloading. The good news is that is shoots great, the bad news is that the handload version is key hole-ing. Velocities are within 80 fps of each other. Has anyone else run into this? Does anybody know what causes this?

 

[timmay]

what bullet it is? Whats the barrel length and twist?

 

[SpeedGoatShooter37]

55 grain Varmageddon out of a 24 inch, 1/14 barrel at 3700 fps. Bullet stability program does show this to be unstable. My question is why doesn't the factory load keyhole with such a small difference in muzzle velocity? I ran the stability program up and down 100 fps with no change, still showed unstable.

 

[timmay]

thats really wierd. Have you pulled one of the bullets and compared them?
Ive bought factory loaded 55gr sierra game king hollow points and they were a little bit different than the 55gr game kings bought as just the bullet. The hollow point was much bigger in the reloading bullets.
Could be some kind of small difference in bullet thats making it keyhole?
I don't know, as you said 80fps shouldn't make a difference that huge.

Have you weighed them to see if they really are 55gr? Could possiblly have gotten 60gr?
That would be an extremely rare thing to happen from Nosler though.

 

[HARPERC]

Just making noise, but my thought is the Varmegeddon is losing integrity pushed at that speed.

I'd slow it down and see what happens.

 

[gohring3006]

Was it cold when you tested your hand loads compared to when you shot the factory ammo?
Temp affects stability....

 

[Bullet bumper]

There has to be something different about the factory bullet .
The reload bullet is quite long at .795 for a flat base .224 so it does come up as unstable .
Also it is possible as previously mentioned that the bullet is coming apart at 3700 fps if the jacket is thin .
I bet the factory bullet is made differently to the reload bullet in some way .

 

[Frank in the Laurels]

Should be fine, gotta be the bullet coming apart of distorting at 3700....try the vmax or sierra ...14 twist should work with 55's..

 

[Bullet bumper]

It's not the weight of the bullet it's the length that sets the twist rate needed .
It calculates as unstable . It could even be a combination of instability and jacket deformation . The thickness of the jacket , the type of rifling , the smoothness of the bore , the amount of fouling present , the length of the barrel , the velocity how hard it's driven are all factors affecting potential bullet blow up.
It's hard to know what is actually getting to the target and showing the keyholing.
The full bullet or just the core . Generally at that velocity if the jacket pops they blow right up and disintegrate . The bullet is long for a 55 grain flat base so it could be made wrong inside and have a very short core causing the bullets center of pressure to be all wrong for a 1 in 14 twist . I would section the two bullets concerned and compare them . Remember the Varmint grenade and how it needed a very fast twist that was because of a very short core and nothing in the ogive .

 

[jgal72]

I'm running 55 grain ballistic tip varmint in my 22/250, 14 twist, 26 inch at 3735fps. No problems

 

[SpeedGoatShooter37]

The extra couple of inches an velocity may be the difference.

 

[Bullet bumper]

I wonder if the Ballistic tips are coming off or canting in some way . It would be good if a bullet could be trapped for inspection .
Something has to be happening to the reload bullet that is not affecting the factory bullet or there is some difference in the way they are made .
Pull out a few ballistic tips and then reload those bullets and see if they keyhole .

 

[4xforfun]

Are you SURE that the factory isn't key holing? My brother was testing a new semi custom 22-250 imp with a 1-14 twist and 55 Balistic tips. He fired 3 quick shots at 25 yards to get on paper and then proceded to shoot groups at 100.....bad groups....TERREBLE groups. Took the gun home and tore it down to check it over and switch scopes. Went back the next day with a different powder and the 55's. Same thing. Now, the holes in the target looked OK both days at 100. He grabbed up all of the targets, including the 25 yard target. One look at the 25 yard target told us all we needed to know.....all 3 bullet holes were sideways...perfect little coppys of a NBT, including the little boat tail!! They just happend to be dead on square at 100 and sraight sideways at 25!! He didn't bother to look the 25 yard target over the day before. Checked out the Berger twist calculator....the 55 NBT isn't even close to being stable out of a 14 twist tube. My question...how many hundreds of millions of 55 grain NBT's had been fired trouble free out of 14 twist tubes over the years??

Measure twice....cut once!!!

Tod

 

[Doghunter23]

Should be fine, gotta be the bullet coming apart of distorting at 3700....try the vmax or sierra ...14 twist should work with 55's..

I agree.. the 52gr SMK has proven to be great at those speeds out of my 1-14 twist 220 swift AI.
53 hornady Amax might be worth a try if you want violent expansion. The SMK shoots bugholes for me.

I think the Sierra has a thicker jacket that holds up better to the velocity, but it still explodes everything pretty good!