Keyholing bullets in 338 lapua/weatherbyorked

[wildcat westerner]

Hello ,
A neighbor returned from Africa where he used a 338 Lapua chambered Weatherby. He asked me to help him with reloading,tuning etc. In checking this rifle, I found it superior to a Weatherby we worked on to get ready for a hunt in the '80's.The recoil pad and muzzle brake were well designed forthis rifle and recoil was manageable for a hunting rifle of this caliber.
I tried some 250 grain S&B bthp ammo and found they keyholed at 100 yards. Other S&B ammo with 250 grain Nosler Bullets struck so far from the other Bullets' impact they hit the ground in front of the target.
All this was very puzzling to me. Weatherby tells me the weapon was made in 2015 and the twist rate was 1-9.3. Obviously I don't want to be wasting expensive factory ammo here, but would really appreciate experienced advice with regard to this caliber and weapon. Jason will be returning to Africa next year and I would like to reload some superior ammo for him for that trip. I am acquainted with robust caliber rifles, have my own .375 H&H, and have fired .416 Rigby's and .458 Winchesters.

WW

 

[RockyMtnMT]

Have you manually checked the barrel twist?

 

[Quicksilver338]

Have you checked bore condition before and after cleaning for any type of fouling?

 

[wildcat westerner]

Hello,
I have not checked the barrel twist manually and the bore appears to be normal in terms of fouling. I shall be checking it this morning for copper fouling. It just seems to me that a barrel with a 1-9.3 twist rate should stabilize just about any bullet in the 250 grain weight category. The wide dispersion of impact at 100 yards from two Bullets of the same weight is an effect I have not encountered before.

WW

 

[Rich Coyle]

Is the bore in the brake adequate and on centerline?

 

[elkaholic]

I assume your friend shot it before the trip and it was ok then?
I wonder if the muzzle (crown) got dinged during the trip?

 

[Quicksilver338]

Some comments may seem too obvious, but make a long list of anything you can think of and comments on here. I thought my 338 barrel was done at 750rds but had carbon fouling caked on that took special attention to remove. Afterwards it's shooting sub half inch and is back to before. Things happen over time and it's best to be methodical about it and there is no stupid question asked!

 

[HARPERC]

..... It just seems to me that a barrel with a 1-9.3 twist rate should stabilize just about any bullet in the 250 grain weight category........WW

It should, but I've had a barrel not as specified. Verifying to easy not to check.

 

[MagMan]

Is there a burr in the brake?

 

[ofbandg]

The last rifle I had that keyholed ended up being caused by a subtle barrel bulge near the muzzle. It apparently happened when the front sight was being sweated on and could only be seen when the bore was sparkling clean and you were looking for it. The strange part was when I fired short shank flat based bullets it grouped not bad but when I used long shank boat tail it would hit the target sideways at 50 yards.

 

[del2les]

If the barrel specs out for caliber n twist, then check the brake alignment and holes for defects n size. I have seen brakes misaligned, under sized, and with other defects. Often, I will shoot a rifle with the brake off to verify then with it on and look for changes.

Of course, If the bore is out of spec, that is another animal

 

[lyotehunter]

First check the crown at the muzzle.that is one thing that will cause that.

 

[ENGUNEER]

I would definitely check the brake to bore centerline. I had one rifle with a brake that the bullets were hitting and it wouldn't hit 3'x3' cardboard at 25 yards (also keyholed when it hit). I bored out the brake a bit and it now shoots nicely.

 

[lyotehunter]

I would definitely check the brake to bore centerline. I had one rifle with a brake that the bullets were hitting and it wouldn't hit 3'x3' cardboard at 25 yards (also keyholed when it hit). I bored out the brake a bit and it now shoots nicely.

Yes the brake also has to have clearance enough to not get a carbon ring that will cause that to happen