Consensus Re Rifle Losing Accuracy?

[Firefighter]

I built a a 280AI, Savage 110 long action,, Shilen, 9 tw, Chrome Moly, 26" w/brake,#4 contour, this barrel was made and chambered and threaded at Shilen Co.,, Bell and Carlson stock w/ bedding block. (Hunting Rifle)

My problem is my groups really open up to >2.0in. after about 8 shots?

a.,,Stats of Barrel, it has 100 rounds through it
b.,,After cleaning, 1st 2 shots are used as fowlers, then the next five are shot, and all five are in a .750 group size.
c.,, After the five shot group I leave gun sitting in a vertical position for 30 minutes for cool down,then I shoot another 5 shot group
d.,,This is when my groups really open up??? Always in a vertical condition

Is my reticles in my scope starting to float at that time? My barrel does not touch stock at that time, Is the barrel starting to relieve at that time? My scope mounts are all tight, My action screws are all tight, no bullet strikes in muzzle brake, I have checked head spacing and is good per gages.

It shoots really well, very satisfied first 7 shots, even when I reload a new load for it, but after that forget it.

 

[Dusty Stevens]

Too many shots. You need a bigger barrel or 3 shot groups. A mirage shade on your barrel will help too

 

[TAJ45]

Good catch on the mirage shade, Destry.
Are you riding again? Heh heh

 

[Dusty Stevens]

Good catch on the mirage shade, Destry.
Are you riding again? Heh heh

No im waiting on a new baby in the next couple days

 

[varget204]

Make sure barrel has clearance in stock,double check action screws, inch pounds,get a barrel cooler

 

[Riesel]

You've got something that after it heats up it does not go back to it's origin. If you clean the rifle does it go back to shooting again for the first seven and then o south again?
I would check the torque on the barrel nut, the torque on the action screws and lastly recheck the bedding. The vertical is a clue somethings awry in those area.
Just my opinion.
Riesel

 

[TAJ45]

Cleaning ? Ruff bore, really ruff, coppering up very early. Bore scope available?
I would think that would give more round shaped groups rather than pure vertical. Head scratcher for sure.

 

[Forum Boss]

Your stock may be heating and then flexing and possibly touching the barrel. Unlikely but I've seen it happen (i.e. stock flex affecting group, though not heat related).

 

[jackson1]

A hunting rifle is not a target rifle. I quickly learned that lesson a number of years ago. With a hunting rifle, I am focused on cold bore accuracy. Like to shoot 10 shot group targets. I shoot 2 shots, pull the target and repeat the next time at the range. When I get a target I like, the rifle goes back in the safe, until just before hunting season, when I take a couple of verification shots. Have a completely different approach with my varmint and target rifles.

 

[Richard Coody]

Hunting rifle the money shot is that first cold bore shot. Take your time with load development. 3 shot groups then put it away.

Now as hunting season approaches i will take that rifle to the range with me every trip and fire 1 cold bore shot to get it dialed in and make sure its ready. Don't clean the bore until hunting season is over.

 

[284winner]

I built a a 280AI, Savage 110 long action,, Shilen, 9 tw, Chrome Moly, 26" w/brake,#4 contour, this barrel was made and chambered and threaded at Shilen Co.,, Bell and Carlson stock w/ bedding block. (Hunting Rifle)

My problem is my groups really open up to >2.0in. after about 8 shots?

a.,,Stats of Barrel, it has 100 rounds through it
b.,,After cleaning, 1st 2 shots are used as fowlers, then the next five are shot, and all five are in a .750 group size.
c.,, After the five shot group I leave gun sitting in a vertical position for 30 minutes for cool down,then I shoot another 5 shot group
d.,,This is when my groups really open up??? Always in a vertical condition

Is my reticles in my scope starting to float at that time? My barrel does not touch stock at that time, Is the barrel starting to relieve at that time? My scope mounts are all tight, My action screws are all tight, no bullet strikes in muzzle brake, I have checked head spacing and is good per gages.

It shoots really well, very satisfied first 7 shots, even when I reload a new load for it, but after that forget it.

#4 barrel I believe is similar to a magnum Sporter so by no means a thin barrel. Shouldn't be overheating in 5 shot strings. Do you have another stock you could mount it in and try shooting it again ? May be a stock issue.

 

[Nick Caprinolo]

A hunting rifle is a hunting rifle and not a target gun. That being said, try fiddling with the action mounting screws. On most rifles the amount of torque is critical to obtain good accuracy on successive shots. Take note, that there may be a difference it the amount of torque in front and back screws. Adjust in small increments. One of my rifles requires a front of 65 lbs and the rear is 50 lbs.

My experience with the one Remington hunting rifle I own in 30-06 is this. First shot is sure to be point of aim. Second shot will be close. third shot will usually wind up more than an inch away. If I wait 10 minutes before I fire the third shot, it will be close to the point of aim. Feel your barrel after each shot. It will most likely be warm after the first shot. Fire two more rounds and you will find that it is hot and with five rounds it should be hot as hell.

With one hundred rounds, the barrel is close to reaching it's maximum brake in period. That is if you followed proper brake in procedures.

 

[hogpatrol]

What scope? Brand and model?

 

[mikecr]

Sounds like it's copper fouling out.
Easy fix if so.

 

[Firefighter]

What scope? Brand and model?

Nikon Black X1000,,6x24

 

[Firefighter]

Thanks for all your replies, I will check all of the items mentioned. I have built 23 guns now, and this is the first one that I've had a issue with. My thoughts and observation of what my groups do, is that my barrel does not like to be shot more than 5 times,,,my first group of 5,,are 3 touching and other 2 are very close,,,I also shot a 3 shot group at 200yds.in a 1" circle,,,these groups were shot with cold bore also.

 

[Firefighter]

My barrel was the first barrel my reamer cut, I ordered the sammi 280AI from PTG, and then sent the reamer to Shilen for chambering. The chamber looks beautiful with no tool lines or chatter. I did break the barrel properly, and it does clean nice with no copper present.

 

[Firefighter]

 

[Firefighter]

I need to treat this gun differently as Nick said,,,I'm so used to my HV or Bull barrels on my Target rifles. Plus the 280AI is burning twice the amount of powder compared to my Target rifles. The barrel on the 280AI is a magnum sporter contour, it does get warm very fast.

 

[Firefighter]

I did notice, the gun shoots better groups with bipod rather than in my shooting rest. I think in the rest, the gun wants to roll to one side or other.