KEY HOLE PROBLEM

[RYEWSKY25284]

I have a browning Xbolt long range max in 6.5 PRC 7" twist 26" heavy sporter with a random key hole problem (see attached ) shooting 147 gr ELD match, H1000 or H4831SC moderate loads. action is torqued per mfg specs scope as well. bedded and full floated, I am shooting off a Sinclair F class bipod and rear bag. when I say random it may be 3,4, 5th shot, not over heated. I am very carefull with reloading, ES 12, SD 4.3, seat depth .050, neck tension seems fine. I am lost, never had this problem with any other guns, first plastic stock I ever had, I am thinking stock, bipod problem? HELP!! hop JE responds to this. Thanks for any ideas. Jim

... Is it possible that your getting bullet separation just before getting to the target?? I've not seen a key hole that shape before. An 8 twist is more typical on the 6.5 PRC. I think a heavier bullet my be the ticket. A lighter bullet would key hole easier.
That's pretty wild. If not for the key hole, the rifle looks like she'll shoot pretty good.

 

[JAYgs8163]

... Is it possible that your getting bullet separation just before getting to the target?? I've not seen a key hole that shape before. An 8 twist is more typical on the 6.5 PRC. I think a heavier bullet my be the ticket. A lighter bullet would key hole easier.
That's pretty wild. If not for the key hole, the rifle looks like she'll shoot pretty good.

If you're going to stay with a lighter bullet maybe try a solid copper bullet and see what happens. Or maybe something with a thicker jacket. Most 6.5PRCs I've seen or the 2 I own are 1/8 or 1/7.5

 

[foul bore]

Have you checked your twist rate I have seen factory rifles way off their stated twist rate

actual twist is 7 1/2 checked 4 times at different locations in bore, loaded some 140gr Sierra to try I am confident this is going to cure, also cleaned carbon ect, super clean

 

[vortech347]

It's the bullet. Until Hornady addresses the 147's coming apart don't trust them. I have seen them come apart in a 1:8 Creedmoor and a 1:7 Douglas barreled PRC.

 

[kkrezz in az]

I have a browning Xbolt long range max in 6.5 PRC 7" twist 26" heavy sporter with a random key hole problem (see attached ) shooting 147 gr ELD match, H1000 or H4831SC moderate loads. action is torqued per mfg specs scope as well. bedded and full floated, I am shooting off a Sinclair F class bipod and rear bag. when I say random it may be 3,4, 5th shot, not over heated. I am very carefull with reloading, ES 12, SD 4.3, seat depth .050, neck tension seems fine. I am lost, never had this problem with any other guns, first plastic stock I ever had, I am thinking stock, bipod problem? HELP!! hop JE responds to this. Thanks for any ideas. Jim

The one in seven twist you have is too fast of a twist for that bullet the rifling is cutting into that bullet and tearing the jackets off

 

[pjmdy]

I have a Savage MSR-15 Long Range in .224 Valkyrie. It is supposed to be shooting heavier for caliber .224 bullets of 90 grains or better. I had problems once with it with recycling and sent it back to the factory where they said it was a gas block adjustment issue. I took it to the range with boxes of various factory made ammo. Keyholing was abundant, practically everything I tried was doing it. I sent it back again, this time it was given a new barrel. Twist rate is 1 in 7. Now it shoots nice tight groups and no more keyholing or recycling issues. It may pay to send your rifle back to the manufacturer.

 

[Rooks]

Confirm twist rate, shoot Berger.

 

[foul bore]

Confirm twist rate, shoot Berger.

did its 7 1/2 and have Bergers on order Thanks

 

[nkyshooter]

"Almost" without question - jacket/core separation - I've had this out of fast twist barrels with light Hornady vmax bullets (very thin jacketed varmint bullets) At middle and up ranges in p-dog field I could witness 2 points of impact on approx 10-20% of my shots over 250 yards ... In my case, they didn't begin failing until out past 200-250 ...

Possibilities ...
1. Faulty bullets
2. Rpm's exceeding bullet design - (rpm's increase with velocity)
3. "Rough" barrel/rifling or crown that is harder on the jackets than "normal"

Things to try ...
1. If you are shooting with either a can or a brake, remove it for testing ...
2. Different bullets - If you have or can get them, maybe try some Berger 140 Hunting VLD's - I've not had any of these separate and I've run them at 2950
3. Slow down your muzzle velocity - stay safe but work your way DOWN the load chart instead of up - if it stops when you get down to the 2400-2500 fps range or even above, it is without question the rpm's
4. Scope the bore looking for anomalies, check the crown VERY closely ...


One of the guys mentioned it above - got to isolate the variable to get to the bottom ...

All that being said - my money is on excessive rpm for the bullet seeing as they are Hornady 147 eldm's (very thin jackets to get the length/high bc) ... (love Hornady by the way - so not hating on them at all)

Groups look good on the ones holding together so I'll be surprised if it is the rifle ...

Good luck and I hope you let us know what you find ...

 

[drstrangelove]

One thing that will destabilize an ELDM every time is damage to the plastic tip, either from improper seating die, pulling and reseating a bullet, jamming it during bolt loading, or velocity so hot it melts in flight from air friction. I have shot hundreds and never seen one keyhole or blow up, but I single shot load on a bench. Mostly use 147's in 6.5prc to 2950. I suspect many of these instances I read about are hotrodders loading from magazines.

 

[walding11]

I have a browning Xbolt long range max in 6.5 PRC 7" twist 26" heavy sporter with a random key hole problem (see attached ) shooting 147 gr ELD match, H1000 or H4831SC moderate loads. action is torqued per mfg specs scope as well. bedded and full floated, I am shooting off a Sinclair F class bipod and rear bag. when I say random it may be 3,4, 5th shot, not over heated. I am very carefull with reloading, ES 12, SD 4.3, seat depth .050, neck tension seems fine. I am lost, never had this problem with any other guns, first plastic stock I ever had, I am thinking stock, bipod problem? HELP!! hop JE responds to this. Thanks for any ideas. Jim

Just had a similar problem with my 300 win mag and finally quit shooting with bipod and used a front end rest with bag under rear of gun, shrunk group size down to .39 MOA at 200 yards.

 

[foul bore]

"Almost" without question - jacket/core separation - I've had this out of fast twist barrels with light Hornady vmax bullets (very thin jacketed varmint bullets) At middle and up ranges in p-dog field I could witness 2 points of impact on approx 10-20% of my shots over 250 yards ... In my case, they didn't begin failing until out past 200-250 ...

Possibilities ...
1. Faulty bullets
2. Rpm's exceeding bullet design - (rpm's increase with velocity)
3. "Rough" barrel/rifling or crown that is harder on the jackets than "normal"

Things to try ...
1. If you are shooting with either a can or a brake, remove it for testing ...
2. Different bullets - If you have or can get them, maybe try some Berger 140 Hunting VLD's - I've not had any of these separate and I've run them at 2950
3. Slow down your muzzle velocity - stay safe but work your way DOWN the load chart instead of up - if it stops when you get down to the 2400-2500 fps range or even above, it is without question the rpm's
4. Scope the bore looking for anomalies, check the crown VERY closely ...


One of the guys mentioned it above - got to isolate the variable to get to the bottom ...

All that being said - my money is on excessive rpm for the bullet seeing as they are Hornady 147 eldm's (very thin jackets to get the length/high bc) ... (love Hornady by the way - so not hating on them at all)

Groups look good on the ones holding together so I'll be surprised if it is the rifle ...

Good luck and I hope you let us know what you find ...

I have done and or in the process of doing all of the above, except removing brake. all looks good through bore scope. explain reason for removing brake, Thanks

 

[Centxshooter]

The 147 ELDM are notorious for blowing up. I had several do the keyhole at close range (100yds). If you video you will see them blow past 200yds. Stopped using them all together in 1:7

 

[jd5521]

I read a thread this morning about a March this weekend with three different shooters, shooting three different calibers having 147 bullets blow up mid-flight. My money is on bullets at this point. All three shared the same lot number.