[ShadowMarine121]

I went straight to the range after boresighting my scope. Got a rough zero @ 25m. So I pushed back the target to 100 and got a grouping. After I adjusted the sight so it shift the grouping.... Only to have it shotgun on me... the only thing I could think of was shooter error but at the same day time I was shooting supported with a Bipod.. Also shot supported in the prone to no avail. Do any of yall have any ideas? I wish I kept the target to post up with this but I was too pissed. About spending 4hrs and 140rds shooting grps of 5s.

Groups @ 25m were within a quarter at the time aprox 60rds had been fired.
Last Group that was fired verifying @ 100m was from 60-80rds
Group "shotgun style" @ 100m were fired from 80-140rds.

So is it possible that the barrel was so fouled after the last group shot that it could cause that?
Wind was pure bliss, nice and flat. Pressure was up more than normal, Humidity was also higher than normal.
It wasn't consistently left, right, up or down. It was wild but on the paper.

 

[Hypo]

How hot did the barrel get?
Describe the gun.
Stock material, pillars or none, bedded or not. Barrel profile. Ammo. Scope and rings.
Is everything still tight?
Scope mounts can get loose or worse, something inside the scope can.
What caliber?
140 rounds is a lot for one range session with a centerfire rifle that isn't a competition.

 

[ShadowMarine121]

SR762 - Firing reloads that had a sub MOA grouping from same rifle.
Reloads - 150gr FMJ 45.4grs IMR4064, 308 LC Brass x2 fired, Win Large Rifle Primers, COAL 2.8mm

Only Additives are a M308 4-12x40 Scope / Mount and a Grippod that deploys into a bipod.
This is the 2ND Time This Optic has been used. It zero'ed flawlessly before Ruger replaced my Upper.
everything seems tight, have the sight mounting hardware marked via paint pen to warn of such things.

Temp the whole time was warm to touch but not "hot" per say. Like I said it was 140rds across 4hrs so there was plenty time between group shots to cool. Since in actuality I was at the range for 6hrs but ended up teaching the woman shooting next to me how to shoot her new handgun lol.

 

[Tim K]

How big were the patterns at 100? Quarter size groups at 100 isn't great, I'd expect 4" at 100 from that.

New bullets or surplus pulled bullets?

If I were to guess, I'd say the parallax adjustment on your scope was not set correctly. That buttstock must make it nearly impossible to get a good cheek weld, and I'd speculate your head position was inconsistent.

 

[ShadowMarine121]

Bullets are brand new not pulled, came from same batch that shot sub MOA at 200meters with Irons.

When I say shotgun I mean from the 20rd shots with

kinda group

to covering from the Left of the 5 Ring to the Right along with Top and Bottom with no group at all. Basically the size of a Basketball almost.
and when I shoot a group I don't move anything period until the full 5rd group is shot. Unless I sneeze lol
The cheek weld isn't terrible but I can get good sight picture with it due to being used to shooting M16s and M4s from my Marine Corps time.

 

[natdscott]

1) Start by checking the FIRST things first: ALL fasteners on the sighting system need to be checked, and if not already paint-pen indexed for both position and torque, you need to do that now.

2) If the shooter is "pissed" at the range, and in retrospect even wonders if the groupings might have been his fault, then it probably was. Lemme 'splain: if you even have a splinter of a doubt that even ONE shot went someplace you didn't want it to, or if you were so frustrated that you couldn't clearly analyze the data in front of you, then it's a really good chance that you were what was screwed up with the shooting platform. I've seen it, I've tried to coach through it, and I've tried to shoot through it myself. Had a Palma match Sunday with the AR-15A2 and I paid good money to get kicked in the nuts several times...believe me, I know what you mean.

3) With match grade barrels, 140 rounds may not be enough to start seeing a reduction of accuracy. Or it might. Whether or not it is visible through the noise of other contributing factors is unknowable to me right now. What IS knowable is that rack-grade Ruger barrels probably drop off in accuracy WELL before then. Some factory tubes can't go more than 20-30 rounds before they need re-rifled with copper cleaners. Think about that, and test it the next time you are out.

I was at the range for 6hrs but ended up teaching the woman shooting next to me how to shoot her new handgun lol.

Soooo...you're telling me it was a pretty good day at the range afterall?! lol


Welcome to the forums.

-Nate

 

[ShadowMarine121]

I was a Marksmanship instructor for a while in the Marines, so I know my way around firearms. But I was needing someone else to tell me to stop being an idiot lol. The barrel is practically brand new at this time, I had just gotten it back from Ruger literally 2 days before I went to the range. The old upper had Cam Pin wear to the point of it actually "shearing" metal, Headspace and timing, along with constant FTF/FTE before they changed it out. And even then I was Always able to get some sort of a group when I fired the damn thing. Thats why I posted on here, I was pissed that I couldn't keep a Zero @ 100yds. Since I wanted to check some new loads I was developing for 150gr / 168gr.

And yea, she was a looker. And 1 of the guys shooting gave me all his 308 brass xD all in all besides the zeroing problem it wasn't too bad.

 

[natdscott]

Why'd you let your cam pin get that bad? They're just an AR-10 pin aren't they?

Anyhow. Ya know, I am good enough with rifles at this point to know, from a basic philosophical standpoint, that there are just some days when I can't make it happen as well as I'd like. There are also the opposite where I can't miss a thing. I've tried and tried to hone in on what exactly causes that variance, and I've asked lots of others, and what I know is that it is almost unknowable. I just take them in stride, and hope that the good days fall on the days when I have to be ON. Since my life doesn't depend on range practice days, if I am off my game, I quit shooting, and that is calculated: if I am shooting below my average, and I know it's not a rifle problem, then I stop because I refuse to drill the wrong things, even if I don't immediately know what my problem is.

Trust me, I get the "hammer through the pain" idea. But what works when shoveling a 4-foot hole in the sand does not always work for other things. Just because you had to in the Corps does not mean that it was best for your performance. I coach with a retired Gunny that shoots Bullseye, and it has taken him 15 years to get to some of what I am saying (and it surely isn't my original thought...we both buy more books than ammo) because of the way the Corps taught him. Their methods work, and are efficient for generating 'acceptable' level performance with firearms, but if one wants to progress to an Elite level, be it in the military or as a civilian, some of those methods (and equipment) are not always best...and so we change what needs changed, mostly between the ears.

Though with teenagers on rifles, sometimes I feel like the USMC method would be good for them....:roll: like, uh.."Go dig a hole, and fill it in, and repeat until you are ready to focus on rifle practice. Minimum reps: 2 holes."

Next time you get that angry on the range, just step back, case the rifle and go help the girl sooner. Only thing better than a day on the range shooting is a day on the range shooting with a girl that wants to shoot. hehehe...

-Nate

 

[Tim K]

You didn't say, did you adjust the scope to be parallax free at 100 yards? Btw, environmental conditions are irrelevant (except for maybe 1" due to wind), temp, baro, and humidity mean nothing at that distance.

 

[ShadowMarine121]

Next time you get that angry on the range, just step back, case the rifle and go help the girl sooner. Only thing better than a day on the range shooting is a day on the range shooting with a girl that wants to shoot. hehehe...

-Nate

Funny enough, I was helping her for the first portion of the day. Once I felt she had the basics down 2hrs later, I went to start on mine. While she was watching and I was doing good I think the first 3hrs of my range time was my peak and then everything after went downhill. But I will be meeting her at the range again this Sunday

You didn't say, did you adjust the scope to be parallax free at 100 yards? Btw, environmental conditions are irrelevant (except for maybe 1" due to wind), temp, baro, and humidity mean nothing at that distance.

I didn't touch the parallax, I don't know much when it comes to all these extras on scopes. I know how to BZO ACOGS, Basic 2 turret scopes and zero with irons. Didn't mess with these "fancy" scopes as I like to put it lol. It never hurts to have all the info written down when you shoot. I honestly keep a "range report" section in my range book. Every time I've shot I've written the conditions at start, along with any changes.

 

[Tim K]

Forget the parallax. I just looked up your scope and parallax is not adjustable and set for 100y. That's not the problem. It's the 4-12, correct, not the 4-16?

 

[natdscott]

But I will be meeting her at the range again this Sunday

Gentlemen, they aren't called Devil Dogs for nothing.

-Nate

 

[ShadowMarine121]

Forget the parallax. I just looked up your scope and parallax is not adjustable and set for 100y. That's not the problem. It's the 4-12, correct, not the 4-16?

****, just saw i had typed that wrong is the 4-16

M-308 4-16x42 BDC 800 from Nikon

thats the link for the scope, and the parallax is set for 50 at this time and instead of the BDC reticle I got the NikoPlex instead.

 

[Tim K]

Do yourself a favor and get a handle on parallax adjustments. Especially at shorter ranges, it can be a very big deal. Prove it to yourself with a little experiment. Leave your parallax adjustment set at 50. Now point the rifle at something 100y away. Without touching the rifle with any part of your body, move your eye left, right, up and down behind the scope. Notice how the crosshairs move all over the target with tiny changes in head position. Now set it to 100. It will be dramatically better. Now fine tune the adjustment until the crosshairs stay planted in the same spot no matter what you do with your head. When you've achieved that, your scope is parallax free at that distance. Go shoot again.