Rilfe Group Fell Off

[Laelkhunter]

Try a thorough barrel cleaning to remove all fouling (carbon and copper), then try again.

 

[Willys]

Based on measurements Im guessing his length is btog and he was chasing the lands ????

 

[cajun]

If I had to guess his cbto seating depth is what he's talking about. That would be .060 throat erosion. The barrel is probably toast. 1000k on an over bore round is about right.

 

[highbrow]

Seems like when my PRS rifle barrels go bad - they go bad fast, like a light switch. I usually see a 50+ fps speed drop (chrono regularly) and the barrel still groups at 100 but start seeing flyers at 500+ yards.

As a high power competitor, we see this especially with stainless barrels. CM barrels tend to gradually fall off and stainless barrels die suddenly. First will see off call shots at 600 but good groups at 200 and 300. Never go to a big match with a long in tooth barrel.

 

[skipglo]

The flyer was the first shot it hit bullseye then the ot 4 moved about an inch low and to the right they grouped. I could understand if the four grouped an then threw the flyer on number 5.

Best flyer to have on a hunting rifle! Cold bore bullseye! .....don't change a thing! Think of the ammo you'll save...a one shot wonder!

 

[Laelkhunter]

Best flyer to have on a hunting rifle! Cold bore bullseye! .....don't change a thing!

Exactly !! The 2nd, 3rd, and 4th shots will be shot at a moving target and 1 or 2 inches won't matter.

 

[ImBillT]

If you've been reloading for 1000shots, there's a fair chance that some of that brass is getting old. Have you checked the length of the actual brass? It's possible for it to get long enough that it starts crimping onto the bullet when you chamber it. That can cause all sorts of trouble.

 

[Seabeeken]

Bore scope pics please

 

[Coyote101]

I bought the rifle new and I was aiming at the bullseye. It has had a steady diet of IMR 4831 50 grain with a nosler 100 grain BT. Pushing the bullet around 3000. When I clean it I always use Barnes swab the barrel wait 10 minutes then run a nylon brush 10 to 12 times. Then dry patch until clean sometimes this can be as many as 30 dry patches. Then an oil patch usually flowed with a couple more dry patches. That has been that rifles life.

 

[Coyote101]

I bought the rifle new and I was aiming at the bullseye. It has had a steady diet of IMR 4831 50 grain with a nosler 100 grain BT. Pushing the bullet around 3000. When I clean it I always use Barnes swab the barrel wait 10 minutes then run a nylon brush 10 to 12 times. Then dry patch until clean sometimes this can be as many as 30 dry patches. Then an oil patch usually flowed with a couple more dry patches. That has been that rifles life.

 

[Koda_]

I bought the rifle new and I was aiming at the bullseye. It has had a steady diet of IMR 4831 50 grain with a nosler 100 grain BT. Pushing the bullet around 3000. When I clean it I always use Barnes swab the barrel wait 10 minutes then run a nylon brush 10 to 12 times. Then dry patch until clean sometimes this can be as many as 30 dry patches. Then an oil patch usually flowed with a couple more dry patches. That has been that rifles life.

Is it possible you just got a flier on the first shot?

Are any of your components from a new production lot? Maybe measure some bullet weights and lengths, maybe the mfg just had something off or different ogive.
New lot of primers?

 

[Coyote101]

it is possible I caught a flyer. All of my components I have had for a couple of years.

 

[TRG65]

My 6.5 Addiction uses 49.8 grains of 4831. I've shot out several barrels and all have gone at 1300-1500 rounds. Like has been said before, they will group at 100, but I'll get flyers at distance and velocity starts changing. Pushing the same amount of powder through a smaller diameter in your quarter bore, you will get even less life.

 

[Koda_]

it is possible I caught a flyer. All of my components I have had for a couple of years.

ok so if we just call the first shot a flier the group below it looks nice.

So then the question is why is it low...?
That can be caused by the scope being bumped or moved accidentally.
Shooting at a different elevation than you zeroed.
Shooting at a different temperature than you zeroed.
Accidentally changing something in your handload process ( I still dont know what your "case length" change means).

Maybe your scale had a bad tare/zero, maybe calipers zeroed off a few thou.

The possibility your barrel is reaching end of life, I will defer that to those with more experience on barrel life than I.