KEY HOLE PROBLEM

foul bore

Well-Known Member
Joined
Feb 1, 2016
Messages
222
Location
texas
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
 

DJ Fergus

Formerly 'djfergus'
Joined
Dec 25, 2015
Messages
2,118
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
Sorry to hear you are having troubles. It's not going to be a powder, brass, bipod, stock, shooting position or scope problem. You can try lighter bullets and it may remedy the problem. This is has come up before. Here's a thread that you can read through that may give you some insight. https://www.longrangehunting.com/threads/nice-groups-at-100-200-no-groups.248241/page-2
 

DJ Fergus

Formerly 'djfergus'
Joined
Dec 25, 2015
Messages
2,118
I'm with Jmw67. That's the first thing I would check. I had 2 Browning xbolts where the twist was not as advertised. On one of these rifles, the bore was significantly tighter for about the last 2.5" of the barrel near the muzzle than it was for the rest of the length of the barrel. I could tell this with a cleaning rod, jag & patch.
 
Last edited:

LVJ76

Well-Known Member
LRH Team Member
Joined
Feb 2, 2019
Messages
1,667
Location
Tucson, Arizona
Have you checked your twist rate I have seen factory rifles way off their stated twist rate
I'm with Jmw67. That's the first thing I would check. I had 2 Browning xbolts where the twist was not as advertised. On one of these rifles, the bore was significantly tighter for about the last 2.5" of the barrel near the muzzle than it was for the rest of the length of the barrel. I could tell this with a cleaning rod, jag & patch.
Agreed, although you mentioned 1:7 twist, that might not be the case. Even the 156gr from Berger needs a minimum 1:8 so you should be fine with the 1:7.

Does this happen 1 on every 5? 4? 3 Rounds?
 

can1010

Well-Known Member
Joined
Feb 27, 2012
Messages
798
that is a common problem with the Hornady bullets. it is not your twist rate , powder , your loading technique , or your gun. the bullet is coming apart mid flight. a lot of treads all over the web about this problem and not one common cause. rough throat and carbon ring are most common
 

DJ Fergus

Formerly 'djfergus'
Joined
Dec 25, 2015
Messages
2,118
This could be quite true, although I haven't had it happen and I've shot a pile of 147s through two different rifles one at 2950 fps and another at 3150fps, both 8 twist barrels. That's another reason I asked his velocity. If it is a 7 twist, it's possible that the jacket could be coming loose.
 

David Emerson

Well-Known Member
LRH Team Member
Joined
Jan 1, 2020
Messages
1,016
Location
Drayton,ND
This could be quite true, although I haven't had it happen and I've shot a pile of 147s through two different rifles one at 2950 fps and another at 3150fps, both 8 twist barrels. That's another reason I asked his velocity. If it is a 7 twist, it's possible that the jacket could be coming loose.
What the evidence shows me. It is not a keyhole. A keyhole shows perfect bullet profile. I think the rpm,s are too much for these bullets.
 

can1010

Well-Known Member
Joined
Feb 27, 2012
Messages
798
This could be quite true, although I haven't had it happen and I've shot a pile of 147s through two different rifles one at 2950 fps and another at 3150fps, both 8 twist barrels. That's another reason I asked his velocity. If it is a 7 twist, it's possible that the jacket could be coming loose.
seen this happen at creedmore velocities in a 1-8 but yet survive my 6.5-300 win mag at 3300 fps in an 1-8
my 6.5 prc 1-7.5 had all kinds of problems after 30 rounds with the 147s and h1000 had to clean the carbon ring then go another 30 or so rounds and repeat changed to faster powder and no carbon ring and problem stopped with the 147s
 

Trending threads

Top