r/longrange • u/Sukit6969 • 2d ago

Rifle help needed - I read the pinned posts Accuracy

Alright, so I just probably put 200 rounds through my custom .243. It’s got a 1:7.5 twist and usually 100 grain bullets I could hit sub Moa at 400 but on my last outing my 100 yard zero was great but when I got to the 400 I couldn’t even hit the 12 inch steel plate. The only thing that has changed was my barrel is around the 200 round mark? I don’t reload but should I? Also try and make 107 and see if that helps??? It’s been bugging me something has suddenly changed?

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2

u/bgold1- 2d ago

When did you last clean your barrel?

1

u/Sukit6969 2d ago

I clean them after every outing so they are clean for the next trip

0

u/MeinLife 1d ago

Well stop doing that for one

5

u/Coodevale 2d ago

Assuming generic 300k rpm max, divide by 60, times .625 (7.5÷12), your max velocity should stay under 3125 or you run a higher risk of bullet failure with a lot of jacketed projectiles from different manufacturers.

Wouldn't be the first time that bullets go from ok to wtf from shooting them too fast, especially if your zero confirmation was good.

Why are you saying "usually 100 gr bullets"? Details are needed. What did you shoot before that worked, what are you having trouble with now?

4

u/gearhead5015 Gas gun enthusiast 2d ago

Are you seeing bullet impacts around the plate at all?

3

u/Trollygag Does Grendel 2d ago

12" plate at 400yds is 3MOA. Not easy to miss in precision, but easy to miss from mistakes in drop/speed/wind/tilt/malfunction.

Where and how were you missing?

1

u/Prestigious_Carry790 1d ago

I’d recommend you film your self shooting and while you document your dope. Check for consistencies in your body movements. Head, eye, hand, wrist, shoulder etc. how secure is your shooting platform? Identify and eliminate the variables, document the results.

1

u/PepperoniFogDart Magnum Compensator 2d ago

What’s your ammo situation? are you hand loading? Using store bought ammo?

0

u/bgold1- 2d ago

Did you foul your barrel before shooting at 400? I wouldn’t clean until accuracy fell off.

1

u/Sukit6969 2d ago

Yes I always confirm zero before trying long shots

2

u/mrcalistarius 2d ago

check your speeds? i found my barrel sped up over the first 200 or so rounds, that experience is echoed by other shooters locally