Reloading for an AR-15

[farmerboyMT]

I picked up my Stag Model 6 just a few days ago.  If anybody is looking for a varminter package AR this is THE GUN.  Right out of the box it shoots well with in the 1/2 MOA advertised.  I managed two groups right at 1/2 MOA or under while I was sighting in.  I do have a question for anybody that reloads for their AR.  I'm using a 60gr VMAX over 24.0 grs Benchmark.  In my bolt gun I use 23.8 grs Benchmark with the same bullet.  What I'm curious to know is 24 grs cycles the action and works for the accuracy but it shoots low.  Do I keep going up or adjust for elevation.  I've never reloaded for a semi-auto rifle before so I'm kinda hesitant to just keep adding powder.  I normally zero at two hundered yards.  Any help would be great.

[targshooter]

The reloading manual will give you the maximum charge for the powder you are using. I have found that my AR15s all like near max (1 grain under) or max loads for proper cycling and consistent shot to shot accuracy. I use a Stag Model 1 that prefers max loads (I use Win 748) with the 55 grain Hornady FMJ BT.

[cjclemens]

If you found a load that works great for both rifles, just re-zero your sight for it.  A reloading manual will tell you where your safe max and min loads are.  Personally, I'd stick with what works.  It doesnt make sense to put your foot through a van gogh.

[jmayton]

Someone correct me if i'm wrong, but there is not a direct correlation between powder charge and POI (i.e. more powder = higher POI).  Just re-zero for that load if it likes it.

[Savage]

It has been my experience that an increase in velocity lowers POI if all other factors remain constant. Less dwell time in the barrel causes the bullet to exit earlier in the recoil cycle. If I had a load shooting 1/2 MOA, I wouldn't change anything, assuming it's a safe load of course!
Savage

[jmayton]

Savage, I've been told the same thing, but every now and then, I'll have a higer velocity load print higher.  Not sure why, I guess it's just the way it interacts with the barrel harmonics.

[Old Syko]

Bullet weight and design (length of bearing surface) will have an effect on poi also.  Heavier bullets print higher out to a point.

[AtlLaw]

Less dwell time in the barrel causes the bullet to exit earlier in the recoil cycle.

I've heard it both ways:  Faster bullet, less dwell time, prints lower, and Faster bullet, less time in flight (= less drop), prints higher.  Gives me a headache trying to figure out which one to use!     So, I just wait 'till after the shot and quote whichever one applies depending on if I hit high or low of my point of aim!   

In my experience the higher velocity rounds print higher on the target but I haven't a clue as to why... 

The only reloading I was going to do for an AR was 80 gr. bullets for the 600 yard line shots in Hi-Power matches.  for the rest of the course I've always shot Black Hills White Box ammo.  After I retired my Garand that is!     For just plain shooting for my own amazement I use ammo from my MilSurp stash.  I do save all brass and if I ever do need to reload anything more then a few rounds I'll send it off to be cleaned, sized, trimmed and primed.  When you're talking 1 or 2 thousand rounds that only sounds reasonable to me!   

[Savage]

In my experience the higher velocity rounds print higher on the target but I haven't a clue as to why.

Guess range has a lot to do with that. As time in flight decreases there is less time for gravity to work on the projectile. The ballistic coefficient would be a factor as well. With a load shooing into - 1/2" I'd dial in the sights and be very happy!
Savage

[jmayton]

I will say that lighter bullets tend to print lower, but that brings in the variables of bearing surface, velocity, and BC as well.  Too many variables.  I agree with ATlaw, just shoot 'em and see what works.  If I get one grouping good (especially 1/2") then I just zero for that load and call it good.

[farmerboyMT]

Well after a weeks worth of messing around with different charges  I've discovered there are no real differences with POI.  I've loaded down as far as 23.5 grs and as high as 24.6, I know this isn't a real big difference but the max load is 24.6.  The 23.5 load had trouble cycling the action sometimes, but they all shoot the same at 100 yds.  At 200 yds there is some difference but not really enough to matter.  I'll post this last query.  When I started I made sure I was 2" high at 100 yds (this is one dot up from the cross hairs, I use a mil dot scope) thinking that should put me pretty close to zero at 200yds.  Turns out I'm just under the dot at 200 with the load I intend to use, 24.1 grs, any ideas on why.  I know with my bolt gun one dot up at 100 is zero at 200.  I'll say again that I'm postively thrilled with the way the Stag shoots and would recommend one to anybody looking to buy an AR.   

[teddy12b]

From 100 to 200 yards I don't think the bullet actually drops that much.  It's all relative, but I zero my long range rifles for 200 yards as a starting point. 

As far as your mil-dots, every scope is different.  I recently tried a little experiment where I used the dots closest to the cross hairs as the aiming point for my sight picture at 100 yards.  The reason I did this is because I wanted to know the distance between the crosshairs and the nearest dot at 100 yards.  When I checked my target I had a bullet hole 3" to right, left, top and bottom of the bullseye.  My mil-dot scope is a nikon buckmaster on top of a 30-06, and now I know I'm zeroed in at 200 yards and the second dot is a hold over for 300 yards.  I don't know if that's confusing or if that helps you with what you're trying to do.  I hope it helps.

[Old Syko]

http://groups.msn.com/TheMarylandAR15ShootersSite/improvedbattlesightzero.msnw

This link may not help much with the mil-dot but will give an idea of how sighting mechanisms work.  What is shown here is a 50 yd. zero that results in a 200 yd. zero.  Yes all things are relative and the only true confirmation can be made by actual use, but it may help to clarify what actually takes place.