I Might Have a Problem Here

[farmerj]

Changes in the POI were significant.

12 moa?!

Yeah, 12 moa.

Consider this.

On the ar, m14, m1 garand, the sight radius is similar. About 22". See anything in common there?

On that platform, to move 1 moa, takes 0.008" over the sight radius. Be it the eye, the rear sight or the front sight.

Little over a year ago, we had a young lady show up on the form, her rifle couldn't shoot worth diddly. She had a nice rifle too. Her issue wasn't even the rifle. She had no cheek weld. She was holding her head off the gun trying to get a site picture. Adjusted the stock, she dropped right in.

Everyone got so wrapped up on ammo or the gun. I was the only.one that went and WATCHED HER shoot and we figured it out.

Now this gun. He's off 5-6".

It ony takes 0.096" deflection on that platform. Rest it on the barrel, poor form etc. There's 12moa error. You can sling up and put that much deflection in the barrel. Now exasberate the problem and REALLY want to get ot corrected. Muscle it even more. Makes matters worse.

OP,

I have time Saturday if you care to shoot and work on this.

[Scoobyvroom]

It would only take about 2.3 degrees of bending to cause that much drift at 50 yards.

Not sure where you got your numbers from but...

50 yards = 1800 inches...
Doing a right triangle one side 1800" the other 5". You can calculate the angle out to be .159°

Sin(.159) x 16" barrel = .044

I can accept .044" of diflection vs .639" That number just seemed outrageous to me.

[engnerdan]

It would only take about 2.3 degrees of bending to cause that much drift at 50 yards.

Not sure where you got your numbers from but...

50 yards = 1800 inches...
Doing a right triangle one side 1800" the other 5". You can calculate the angle out to be .159°

Sin(.159) x 16" barrel = .044

I can accept .044" of diflection vs .639" That number just seemed outrageous to me.

That is what happens when you are tired and doing too many projects at once and forget to convert units. Sorry about that.

[farmerj]

Was out at the range dialing in my new scope on my AR15. Had the gun on a front rest and sandbag in the rear and got is zero'ed and then all of a sudden it was shooting about 5-6" high at 50 yards. I finally figured out that when I had the hand guard sitting on the rest it shot really well (less then 1"groups at 50 yards with factory ammo) but when I inadvertently had the front of the gun sitting on just the barrel it was shooting about 5-6" high. I went back and forth several times and it was doing this consistently. Being new to AR's and rifles in general is this normal or do I have a problem with my gun? I suspect I need to re torque the barrel nut but if it was loose and moving around I would think my shots would be all over the place.

This is a home built AR, mega billet upper and lower, spikes barrel, midwest industries hand guard.

so what ever became of this?

[Synergy]

Sorry guys, I haven't done a dam thing with this since I first posted, plan on bringing it into Atomic so they can go over it.

Where do shoot Farmer, I'd be glad to hook up with you sometime if your still interested. I shoot at Delano but am always looking for other places to shoot.

[farmerj]

Sorry guys, I haven't done a dam thing with this since I first posted, plan on bringing it into Atomic so they can go over it.

Where do shoot Farmer, I'd be glad to hook up with you sometime if your still interested. I shoot at Delano but am always looking for other places to shoot.

I am busy this and next weekend. Will have to see.

Don't really have a place to shoot much. All the ranges I normally would have used are under water at the moment.