Issue with accuracy once past 100 yards--anybody have this problem?

[dougduey]

I worked up what I thought were some really nice loads for my 300WSM using a 180gr Accubond. Was getting sub moa at 100 yards. So, I was really happy and wanted to set zero at 200 yards. My issue is, my cold barrel first shot is right on the money, but my next shot climbs 4-5" high. The barrel is a little warm but not hot. At first I thought that maybe it was user error and I was pulling when I shot (since I was using a bipod and rear bag and not my leadsled), but if I let it cool down completely and then take a shot, I'm on the button again and the same issue arises if I take a follow up shot. Is this an instance of the barrel being too warm and/or maybe too "hot" of a load? I'm shooting a Sako 75 with a 24" barrel with an 11 twist. My reload data is as follows. All have Winchester nickel brass and Winchester LM primers and an OAL of 2.860. Using Hybrid 100V 65.5 gr, RL17 65.0 gr and RL19 68.5 gr with the 180gr Nosler Accubond. The RL17 and Hybrid 100V are pushing about 3050 fps and the RL19 is 2970 fps.
Any advice/help would truly be appreciated

 

[dkhunt14]

Sounds like a bedding issue. I would try h4350 for that light of bullet. I also like federal primers. If you can't get the Accubond too shoot try Berger VLD hunting bullets. Do you clean the barrel regularly? Matt

 

[Lefty7mmstw]

sounds like barrel, bedding, or the rifle doesn't really like the bullet. I've steered away from the wsm's as my pops and brother have both had flaky long range accuracy with theirs... Likely crappy production bbl.'s though... a win70 and a ruger.

 

[Dosh]

DD, loaded for a friend's 300 WSM. 185 Berger VLD, H4350, 215M primer and Federal brass. Started at 200 yds. After tweaking charge and some seating depth it just got better at 3,4,and 500 yds from a Savage 116 bedded in a laminate stock. This rifle shot very poorly using factory ammo and prior to being bedded.

 

[Rick Richard]

Re: Issue with accuracy once past 100 yards--anybody have this problem?t m

I am more inclined to believe it may be a barrel/bedding issue. I would inspect the barrel to see if it is free floated and again after it has been warmed up. If that does not solve the mystery, then bed the action. I Don't think it is necessarily a bullet problem since it is throwing POI that far off. AND FINALLY if that does not work, then you have the choice to replace the barrel or sell the gun.

 

[Greyfox]

Re: Issue with accuracy once past 100 yards--anybody have this problem?t m

You mentioned that your 100 yard accuracy was good, with sub MOA performance. How many shots at 100 and is it still repeatable?. It seems unlikely that consistent 100 yard accuracy wouldn't extend to 200 yards. If you could replicate your 100 yard results with no dispersion, I would be more likely to suspect that something is going on with the bipod/rest/hold set up. You mentioned that you switched from a lead sled to a bipod when moving out to 200 yards. If you replicate your original 100 yard results, I personally would try 200 yards with the exact same set to rule out this possibility. I saw something similar happen to a shooter at range a while back. He was getting "bounce" with his bipod. Just a thought.

 

[Capt RB]

Are you adjusting your parralax in your optic?? If yes put it in your sled and shoot the 200yd. If that improves the group your forend may be hitting the barrel when on the bipod. Or if your stock has the pad you may have to play with that. Hammer forged barrels are made under the stress of being pounded by hammers. This will cause verticle stringing as well as other anomalies in your group as it heats up. If it is free floated take a match book and cut 1/2" strips and put under the barrel for upward pressure. Use a fish scale by pulling at the sling stud to measure how much pressure you have. 5-15# is what was common on the winchester featherweight push feed.
I

 

[roninflag]

i always shoot off of a pedistal and sand bag; never a sled or bipod.

 

[FearNoWind]

I find Alliant powders (all of them) to be somewhat temperature sensitive. However, with the muzzle velocities you posted I don't see any reason why the loads you're using (as long as they're not excessive) shouldn't work just fine.
With the 1:11 twist, your 180 grain AccuBonds should stabilize beautifully in the range of velocities you posted.
As previously mentioned, I too would look at the bedding and the amount of free float allowance you have within the barrel channel.

 

[g0rd0]

It may just be a bedding issue as stated. Go back and try a couple of shots then with the barrel still hot/warm and left on the pod try to slide a cleaning cloth along the bottom between the barrel and stock. On my Savage I can slip the yellow cloth that came with the uncle mikes kit all the way down to the barrel nut.
If this is not your issue try a powder more suited to large capacity cases like RL22 or 25, and IMR7828 with mag primers

 

[Bravo 4]

Re: Issue with accuracy once past 100 yards--anybody have this problem?t m

You mentioned that your 100 yard accuracy was good, with sub MOA performance. How many shots at 100 and is it still repeatable?. It seems unlikely that consistent 100 yard accuracy wouldn't extend to 200 yards. If you could replicate your 100 yard results with no dispersion, I would be more likely to suspect that something is going on with the bipod/rest/hold set up. You mentioned that you switched from a lead sled to a bipod when moving out to 200 yards. If you replicate your original 100 yard results, I personally would try 200 yards with the exact same set to rule out this possibility. I saw something similar happen to a shooter at range a while back. He was getting "bounce" with his bipod. Just a thought.

+1
If the only variable that has changed is the rest you used then there is where you should start. If you are consistently getting good groups at 100 then bedding, the powder you use or your load shouldn't open the groups up several fold at only 100 yards more.

 

[dougduey]

Thanks for all the input. I may be the source of the error so I'll try to see if the bad results show up when I use a lead sled. It may be how I was shooting off the bipod that day. I attached a photo of my 3 shot sub-moa group at 100 yards using Hybrid 100V

 

[tailbon3]

That's a fine looking group. Tikka/Sako makes a nice 300 wsm rifle. My brother got one and the very first load I made up for him shoots just that size group. I was impressed and/or lucky

Reloader 19 - 69.0 gr
165gr Nosler Ballistic Tip
CCI 250
Winchester brass
2.83" COAL

 

[Punisher]

Cold bore shots are a fact of reality for some rifles. Some shooters "don't believe in cold bore"

Let me explain why.

Experienced shooters and tinkerers have showed me that if your rifle exhibits cold bore preference, you need to completely bed your action. That means on both contact points under your action, down your pillars and UNDER YOUR BARREL! Or at minimum, under the chamber.

I learned this through experience. I watched my rifle do it and I watched bedding fix the problem.

I am shooting a Bell and Carleson M40 stock with aluminum bedding block... It still needed to be bedded.