split groups ????

[deadidarren]

gday all has someone got an answer for this it was shooting this load at .75moa
on a regular basis and nothing has changed same loads same batch ????
every thing is tight .

the rifle is a rem sendero 7mm rem mag and the load is rem brass hornady sst 162g
71g of H1000 for 3040 av for 5 shots and cci 250 p
rifle has about 120 rounds down the tube.

thanks in advance .


cheers Darren

 

[WyoElk2Hunt]

How many shots were fired at one time was the barrel hot or did you give it time to cool? Was the barrel freshly cleaned? Just a few of the possibilities.

 

[benchracer]

gday all has someone got an answer for this it was shooting this load at .75moa
on a regular basis and nothing has changed same loads same batch ????
every thing is tight .

the rifle is a rem sendero 7mm rem mag and the load is rem brass hornady sst 162g
71g of H1000 for 3040 av for 5 shots and cci 250 p
rifle has about 120 rounds down the tube.

thanks in advance .


cheers Darren

Double grouping is a classic sign of bedding issues. Check your action screws for tightness and your barrel channel for contact points. Your rifle stock should have an aluminum bedding block, since it is a Sendero. You might need to check your action fit to the stock and skim bed if needed.

 

[gilmillan1]

In addition to all of the above mentioned observations, this can also happen if you don't turn neck cases. Neck turning allows a rifle to shoot at more consistent speeds.

 

[Dosh]

Darren, had the same occurrence with a friends rifle. Checked everything, but found the scope rings were a bit loose. Tightened to spec and it happened again after 40+ rounds so he finally used Loctite and he is back to the tight groups. The bedding would help a lot too. Good luck

 

[dig]

Would concur probably a bedding issue, however paralax may also cause this. Ensure you have the same mount into the rifle every time.

 

[Garycrow]

Darren, had the same occurrence with a friends rifle. Checked everything, but found the scope rings were a bit loose. Tightened to spec and it happened again after 40+ rounds so he finally used Loctite and he is back to the tight groups. The bedding would help a lot too. Good luck

I had the same thing happen & it was because a scope base screw was too long & bottoming out against the action threads. It would let the mounts shift if the scope was bumped. It was maddening to track down but once I figured it out it just took a few quick file strokes to shorten the screw & fix it.

 

[Joel Russo]

Neck turning allows a rifle to shoot at more consistent speeds.

Could you please elaborate on this.

 

[LoneTraveler]

This is one I have been involved in several time. Did the rifle shoot one group, Then change point of impact for the other group, or did it jump back and forth between groups? When I deal with a jump around I like to look through the spotting scope and have a target on my bench and mark each shot on target for reference and check the cronograph. Paralax in the scope, Cheek weld to stock, loose scope bases, and screws, Uneven action screw torque, bedding problem, and Turn cartridge necks for uniform bullet release. A real good list of possible problems. A weak firing pin spring, A bad lot of primers, Or a bench with a slight move in it when you relax for the shot. Shooting the gun through a chronograph may tip you to a primer or firing pin spring problem by velocity change. Make sure the bolt is down in the proper locking position. I have seen guns shot on a range that if the bolt jerked it would change point of impact. Good Luck and let us know when you find the problem.

 

[deadidarren]

thats one reason i like this site just look at all the great advice thanks

now all the mounting had where is good the one thing is the bedding

i noticed when i had the trigger off the bedding area was VEREY sloppy

so i think a skim job is in order.

and with all my shooting the barrel is never aloud to get hot, this was the

order of fire.

cheers D

 

[Pbike257]

If you shot this on a partly cloudy day, you could have two or three of the shots will a cloud was over the target, and the rest when the target was in the sun. Image shift, a result of mirage can cause you to actually be aiming at something you think is the target. when the target hasn't actually moved. In benchrest you hear about "dropped shots", That is a classic target that fits the description.

Paul

 

[deadidarren]

If you shot this on a partly cloudy day, you could have two or three of the shots will a cloud was over the target, and the rest when the target was in the sun. Image shift, a result of mirage can cause you to actually be aiming at something you think is the target. when the target hasn't actually moved. In benchrest you hear about "dropped shots", That is a classic target that fits the description.

Paul

group was shot at 0100

 

[stomp442]

Another thing you might want to check is the bullet weights. The hornady SST bullets have been horrible for me in the past especially in 7mm and 308 calibers. I have had some be as much as a grain and a half different than what is written on the box. Generally with the weights being lower but I have had some heavier too. The one that takes the cake for me is weighing a 308 cal 150 SST that actually only weighed 136 grains. I only use an SST for break in or fouling. The SST line has been the worst for consistency in my experience I have never found these kinds of problems with the Amax or Vmax lines. Something to look into.

 

[Dosh]

Could you please elaborate on this.

+1 enlighten me.