So where do I go from here if my OCW produces this?

[Iamero]

Shooting a factory R700 SPS 308 win varmint cut to 18” with a suppressor. Launching some 178 amax that I have on my bench. Hornady book shows 2.800” OAL and I loaded to 2.810” as I don’t have a hornady modified case right now (thought I did).

Hodgdon showed 40.0 min and 42.7 max on H4895. I started at 41.0 and did 3 shots of the following:

- 41.0gr
- 41.3gr
- 41.6gr
- 41.9gr
- 42.2gr

By the 42.2 the bolt got stiff and got some swipes so definitely not going back that high. Here are the results:

Bottom group is my min (41.0gr), top group is my max (42.gr).

Top left is 41.3, bottom left is 41.6, bottom right is 41.9.

What I am worried about is how great the variance is in accuracy between the 41.0 and 41.3gr. If I get any pressure or velocity spike because of a hot day, I would assume my accuracy goes to shit.

Do I load a little lighter at 40.7 and try it out, switch to a slower powder, switch seating depth, or get a different weight bullet? Looking for some input on what you think is best.

 

[Iamero]

Little update:

Shot 40.7 to see what would happen. Kind of same story as the other middle loads. 1” groups at best.

 

[spife7980]

You load of 5 each of 40.9, 41, and 41.1
If they don’t go to hell then you’ve found your load.

 

[supercorndogs]

Every factory Remington 308 I have had, a 178 a max will fall out of the case before it touches the lands. I don't see anything that makes me think node there. The test size is too small. If you think you have a node, I would run a length test on it. You might be surprised how much it can tighten up your groups.

 

[padom]

My best accuracy came from 178 Amax loaded LONG at 2.88" in my Rem 700 5R. 4064 was my go to buy H4895 was very accurate as well just slower.

You do know an OCW has nothing to do with looking for accuracy. Your looking for consistent POI. You adjust seating depth after to shrink your group size.

 

[Iamero]

Why do I see such drastic changes in accuracy depending on the powder charge then? And if that’s the case then how does factory FGMM Sierra 168SMK ammo shoot so well from gun to gun even though in most cases it has a pretty good jump to the lands?

 

[Iamero]

Shot the 41.0gr again and the same 2.810” and 2.830” OAL today.

The 2.810” that was all touching yesterday was like 1.5” today.

The 2.830” tightened it up a little bit but still nothing to write home about. Fighting mirage a bit, but not enough to do a 1.5” group.

Was the one yesterday a fluke? I was hoping I had some 168s around but not seeing any. Might run up to cabelas just to get something else to try.

 

[supercorndogs]

Why do I see such drastic changes in accuracy depending on the powder charge then? And if that’s the case then how does factory FGMM Sierra 168SMK ammo shoot so well from gun to gun even though in most cases it has a pretty good jump to the lands?

FGMM is in a node. FGMM uses the SMK which is largely touted as not being very sensitive to jump. Although I have had good luck jumping a maxes in factory chambers. Most of the factory barrels I have owned would open up to at least 1 moa with a good load as they got hot. I couldn't look at your test and tell you anything. I use OCW pretty regularly.

My length test usually involves 3 lengths at least .02 apart, not including my original testing length. I usually start .030, so I can't test say.015 ,.035, .055. I will test smaller increments around which ever one is best, if its not "good enough." I usually find something that works without testing past the 4 lengths that have been tested..

Have you tested this rifle with FGMM because you could have other problems not related to the load. It doesn't look promising. There are not enough shots there to say, but they seem to be grouping in several different locations. This often turns out to be a bedding problem. If its not a rifle problem I would try a different bullet.

 

[Iamero]

It’s sitting in a Magpul hunter on this one. That could be part of the problem too, but who knows.

The reason I’m starting to think it’s a gun/barrel issue and not load issue is because of the groups I just shot. I picked up some factory Hornady 155 BLACK and Shot two groups.

Bottom picture is the first 6 shots (upper left most shot was a pull on my part). First picture is the next 4 shots. Pure garbage, which makes me wonder if it’s the factory barrel or the stock.



If it’s the barrel then I’ve got a replacement blank sitting at Spinners Fit & Chamber ready to go on. Just didn’t want to pay the smithing fees and all just to find out the chassis or my trigger is crap.

Checked everything to make sure it’s torqued to spec and tight. We are good there. I’m also running all this with my suppressor on. Would that affect groups negatively or no?

 

[supercorndogs]

Does the magpie have the aluminum bedding block or V block? Loosen the rear action screw and see if the rear tang lifts away from the stock.

 

[Iamero]

Loosened the back screw and the tang stayed put.

I shot two 5 round groups and labeled the order. Let me know if that gives you any indicators.

 

[Iamero]

Maybe I’m just a bad shot now after shooting my 50 haha

 

[supercorndogs]

How many rounds down it? I have had to JB paste a rough factory barrel when new, or do the same thing to remove a tight spot in the bore after a bunch of rounds. IT keeps looking better and better.

 

[Maxduty]

I've got a Mossberg .308 that I sent back to have a new barrel put on. Couldn't get that gun to shoot after breaking in and JB pasting it. New barrel and 60 rounds have settled in in.

 

[STI_1911_Guy]

What kind of accuracy are you expecting (or would be satisfied with) to get out of the factory barrel?

 

[Iamero]

I guess a consistent 3/4 or at least 1” with custom hand loads would be normally. But my 3/4 load goes to 1.5” randomly the second time I Shoot it.

 

[STI_1911_Guy]

I would say 1 moa should be achievable. Try some FGMM and if that or your handloads won’t shoot then I would say it’s more the rifle

 

[1J04]

Here's a thread that was on here last year regarding your stock. And yes, we could look all over the web and find unhappy campers with your stock, but I trust the folks I know on here.

http://www.snipershide.com/shooting/threads/magpul-hunter-700-stock.6377922/



I have to ask, how many inch lbs of torque are you using on your rig? Or are you even using a torque wrench? I'm gonna guess it's suppose to be between 50-60 inch lbs. Obviously a HUGE list of "what about" could be asked, but this is a good start.

 

[Iamero]

Yea I have the stock to action at 55 per magpuls recommendation. Base to action at 25, rings to base at 45, and rings to scope at 18.

 

[1J04]

Yea I have the stock to action at 55 per magpuls recommendation. Base to action at 25, rings to base at 45, and rings to scope at 18.

Perfect. Scratch that off the list. So you're not gonna get the easy fix it appears. But maybe you still can.... Regardless of your twist rate, I'd try a box of FGMM 168's and 175's. Half a box at 100 each and the other half at 200 and see what happens. If that doesn't do it you've obviously either gotta go back to square root one, or ya got a non-shooter. Maddening I know, but I'd do the FGMM before playing with a load right now. It may just not shoot. Meh.

 

[supercorndogs]

I would try it minus the suppressor and suppressor mount as well. You just have to eliminate one thing at time. FGMM is a very good way to do that in an unknown rifle, and unknown load.