zeroing issue

[ktjones]

So I have this new Howa 1500 in 300wm. I finally got to take it to the range today for the first time. I was following the break-in procedures (as I remembered them from the pamphlet that came with it) and then went to trying to zero my new Vortex scope. At 100yds, cold bore, I'd fire 1 shot about 3/4" low. If I waited 5-10 minutes between shots, I'd put 3 holes touching. So I move it to the bulls eye, wait for the barrel to cool then shoot and sure enough, bulls eye. The problem arises if I put a round down range, then don't wait for the barrel to cool, my next shot is about 1.3" higher. If the barrel is warm (I'm talking a round every minute or so, not one right after another), they'll group 3/4", but an inch or so higher than cold bore.
Just wondering if others experience this and if there is anything to be done for it.

Thanks,
Kyle

 

[J E Custom]

So I have this new Howa 1500 in 300wm. I finally got to take it to the range today for the first time. I was following the break-in procedures (as I remembered them from the pamphlet that came with it) and then went to trying to zero my new Vortex scope. At 100yds, cold bore, I'd fire 1 shot about 3/4" low. If I waited 5-10 minutes between shots, I'd put 3 holes touching. So I move it to the bulls eye, wait for the barrel to cool then shoot and sure enough, bulls eye. The problem arises if I put a round down range, then don't wait for the barrel to cool, my next shot is about 1.3" higher. If the barrel is warm (I'm talking a round every minute or so, not one right after another), they'll group 3/4", but an inch or so higher than cold bore.
Just wondering if others experience this and if there is anything to be done for it.

Thanks,
Kyle

You might be leaving the round in the chamber to long. get into firing position and close the bolt at the last min.

Get the round off as soon as you can to keep from heating up the case and powder charge.

J E CUSTOM

 

[ktjones]

Honestly, I've never really thought about that. There are so many minute factors to consider.
That being said, I wasn't leaing the round in for long at all, maybe 15-25 seconds. I would get things lined up before I got behind the gun (shooting from a vise trying to take the human factor out), once it was lined up, I'd put the rnd in and close the bolt, probably less than 20 seconds to make minor adjustments and squeeze off the round. Not that I was doing it purposely, like I said, that was a factor I hadn't thought of. When I was waiting for the barrel to cool, I didn't have a round in and I'd leave the bolt open.

wow, lots more to think about. Thanks a lot.

 

[Dr. Vette]

Additional thoughts -

Which stock? flexible plastic stocks aren't well known for repeatable accuracy. The flex, they put pressure on the barrel in an inconsistent manner, and are made for a price point not for accuracy.

What scope? I've spent plenty of time chasing parallax problems in scopes at all price points.

The vice isn't helping you at all. You need to learn how to shoot in a repeatable manner, every time. I used to use a Lead Sled, but stopped using it years ago and have done much better without it. Use a good rest (I usually use a Caldwell bag in front, sandbags in the rear) and get solid - see this thread:
http://www.longrangehunting.com/forums/f116/importance-being-solid-91149/

I usually suggest taking a .22LR along and shooting groups of 10 at 50 or 75 yards. When the groups settle down nice and small start shooting your larger rifle. You can also shoot the 22 between rounds of the 300 WM. I suspect you may be surprised how much it helps.

 

[FearNoWind]

If your Howa has an overmolded stock (usually some form of reinforced polymer with a covering of rubber of other material) it could be part of the problem. I'd suggest making sure everything was properly torqued and free float was verified before you look at anything else. Check to make sure there isn't something in the barrel channel (sometimes there's a bit of the rubber covering at the front of the barrel channel that touches the barrel) and that nothing in front of the barrel lug contacts the barrel's underside.
You may not be able to find any flex in the stock if you put pressure on it by hand but the flex point that you can't readily test, at the front of the action, could be contributing to your problem.

 

[ktjones]

Additional thoughts -
Which stock? flexible plastic stocks aren't well known for repeatable accuracy. The flex, they put pressure on the barrel in an inconsistent manner, and are made for a price point not for accuracy.

It has the Hogue over molded stock. Fiberglass stock pillar bedded with a rubber overmolding.

What scope? I've spent plenty of time chasing parallax problems in scopes at all price points.

I topped it with a Vortex Diamondback 4-12x40 with Leupold rings

The vice isn't helping you at all. You need to learn how to shoot in a repeatable manner, every time. I used to use a Lead Sled, but stopped using it years ago and have done much better without it. Use a good rest (I usually use a Caldwell bag in front, sandbags in the rear) and get solid - see this thread:
http://www.longrangehunting.com/forums/f116/importance-being-solid-91149/

I'll certainly take this advice to heart. I only use the, I say vice, it's more like the lead sled, to take as much of the human factor out as possible when I'm sighting in a rifle. Then anything after that is my fault.

I usually suggest taking a .22LR along and shooting groups of 10 at 50 or 75 yards. When the groups settle down nice and small start shooting your larger rifle. You can also shoot the 22 between rounds of the 300 WM. I suspect you may be surprised how much it helps.

I will definately take a 22 with me next Time. That's a great idea. I shot a few rnds of .308 after shooting the 300 for a while and it felt like a BB gun.

One more thing I should have mentioned first off and this might be most important, I was shooting Hornady American Whitetail factory loads. I haven't loaded anything for this rifle yet (I just got it) and I was doing the barrel break-in.

Thing is, I can shoot tight-ish groups, it's just that my group shifts from cold bore to hot. If I've shot several in a row, it's a sub 1" group, just 1" or so higher than the cold bore shot.

 

[Barrelnut]

Might also be the barrel. I think Howa's use hammer forged barrels. The barrel may not be totally stress relieved after the hammer forging. Consequently the point of impact changes as the barrel heats up. Usually called barrel walking. It's not uncommon with sporter weight hammer forged barrels. Take your time, keep the barrel very cool, as you were at the start and see if consistency returns. It's probably not you or the sled.

 

[ktjones]

That's exactly the kind of thing I'm afraid of. I'd hate to think I dropped a pile of cash on a gun to find out that there is a defect in the barrel. No real way to prove that or quantify the defect enough to satisfy the manufacturer either I'm guessing. I may try to contact them just to see what they have to say about ut

 

[Mikecr]

I don't see it as that bad of a problem myself. It's a hunting gun -not a BR gun.
So if you're cold bore accuracy is good, and you setup for good shots, you shouldn't need a fast follow-up anyway. And believe me, cold bore accuracy is a lot harder to develop than hot barrel grouping.

 

[Dr. Vette]

It has the Hogue over molded stock. Fiberglass stock pillar bedded with a rubber overmolding.

I have the same stock on a Vanguard 30-06, so I'm familiar with it.

I bedded the recoil lug on mine, and made sure the barrel was floated with no contact between barrel and stock. You can bed these, at least the plastic portion, but you can't bed the rubber portion. Bedding the front lug gets you most of the benefit anyway, and will make it more solid. I've done it twice now on plastic-based stocks using Devcon steel putty with very good results. Be sure to rough up the plastic ahead of time where the bedding will go, and then wash it clean before bedding it. If I didn't have the rifle packed and ready for deer hunting I'd remove the action and show you what it looks like.