Hope to get out to the range this weekend and sight in my new AR 15 .. Weather hasn't co-operated the last 2 weekends ..

It has the 5.56 NATO 1/8 5R barrel and was wondering what grain ammo should I use to sight it in ?? and is there a particular brand that would be better then others to use ??

I've read what grain should work with the 1 to 8 twist but can't find what people use for the first sighting of the rifle ..
?? or if one grain size would be better then others for doing that !!

I bought a box of 45, a couple of boxes of 55, and a box of 62 grain ammo .. Once I find out what it likes the most I will be a case ..

Also how accurate should I expect the Magpul sights on it will be on the first shot straight from the factory ?? are they pretty well sighted in at the factory ??

With the 1/8 twist, either the 55's or the 62's would be your best bet to shoot. Factory sites should be close, but I would check the bore site at 25 yds to start.

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I suspect that you may find the 62 grain shoots best but different rifles can do things that make you scratch your head sometimes. One thing I have noticed is that the weight of the bullet has a lot LESS influence on elevation changes when compared to what is seen with a handgun.

As for your question about your iron sights, I have yet to see any aftermarket sight shoot to the Point of Impact out of the packaging. So, plan on sighting in your rifle and insure you have the tools needed to do this BEFORE heading to the range. Yeah, I have driven all the way to the range and found when I got there I had left the front post tool at home.

If it were me I'd sight it in with what I plan to shoot most. I agree that the 62 grain may be more accurate in an 8 twist barrel but if you can get acceptable accuracy with 55 grain you'll save money on ammo.

As to factory loads I like PMC X-TAC, it's also excellent brass for reloading. You'll save some money buying it by the case from SGAmmo.com

1/8 needs a heavier bullet ... my AR likes 69 grain

Tried 55 gr but they seem fly all over on me

Pulled the below from a web site .......................

Common AR-15 rates of twist vary between 1:7 and 1:12, but why should you care what your rate of twist is, right? The reason is because different bullet weights perform better with certain rates of twist. So if you are just going to go plinking and do short- to medium-range target shooting, you may be happy with 40 grain bullet weights, which would mean a 1:12 rate of twist would be ideal for you.
If you are shooting long range, or want more penetration, you want a heavier bullet in the AR, such as a 62- or preferably a 77-grain. 62-grain bullets prefer a rate of twist around 1:8 and 77-grain bullets weights favor a 1:7 twist rate.

All of this being said, these days finding ANY AR-15 ammo is almost like winning the lottery, and if you are lucky enough to find any at all it is likely going to be the most common bullet weight which is 55-grain (a 1:9 twist rate). Ideal rates of twist for a particular bullet weight are somewhat subjective; however opinions will not vary greatly among the experts.

Bullet Weight: The Ideal Rate of Twist
So to simplify this for you, here is a chart you may want to print:

Bullet Weight Twist
40-Grain 1:12
55-Grain 1:9
62-Grain 1:8 or 1:7
77-Grain 1:7 or 1:8
80-Grain 1:7

As you can see from the chart, the heavier the bullet you want to shoot, the faster the rate of twist should be to most effectively stabilize the bullet. It’s not that you can’t shoot AR ammo that is on one end of the spectrum through a barrel with a twist rate at the other end of the spectrum, it’s just not ideal. You won’t get maximum effectiveness of your ammunition. One thing that can happen is over-stabilization; this occurs when you shoot a bullet through a barrel with too fast of a rate of twist for that particular bullet weight.
Here’s an example: you shoot a 40-grain AR bullet through a barrel with a 1:7 rate of twist; the bullet will over-stabilize and this will make the bullet not fly completely true at longer ranges. But you wouldn’t want to shoot a light AR bullet at long ranges anyway.

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Thank You
Wayne

I do most of my shooting at 100 or 200 yards and have found, surprisingly, that bullets of different weights (55-75 grs.) shoot fairly close to the same point of impact, i.e., within a couple of inches or so. I've verified this using three AR-15s, two scoped guns with 16.1" barrels and one aperture-sighted gun with a 20" barrel, all with 1 in 7" bores.

This includes a variety of factory ammunition, but mostly handloads loaded to approximate factory muzzle velocities. Shooting was done from a benchrest with Protektor leather bags and a Hart pedestal front rest.

The following may vary from one person to another, but I've found that shooting from a less-supported position (offhand, using a makeshift rest, or supporting the handguard / forearm with weak hand between rest and gun) will consistently bring groups lower by about 2" at 100 yards and 4" to 5" lower at 200 yards.

No such thing as overstabilization. A quality barrel will shoot well with almost any bullet weight as long as the twist is fast enough to stabilize the bullet. A 1:9 may stabilize a 75gr bullet and certainly will stabilize a 69gr bullet and lighter. You run into problems when you have a rough barrel that damages the jacket on lighter bullets and you get comet tails on your target.

This is the right answer... and choosing the projectile will depend on what your use will be after sight in. You would use a different projectile for hunting than what you might use for ringing steel, for example.

And let's say you sight in with a 55 gr, fmj round and all is good. Then you get an invite to go on a hog hunt and TSX 55 gr bullets are what you buy for the hunt... Your rifle is not sighted in for the TSX rounds and they may have a different POI than the FMJ rounds you sighted in with. It is bullet dependent.

So, if your use is going to be shooting paper, for your first trip shoot some of each one you bought and shoot for groups. See which round groups the best out of your rifle and go from there.

1/8 should handle 55 gr just fine. Your issue is either with a particular brand of ammo, or specific to your gun...

This is where I start..................

Just to initially zero an optic or irons the ammo makes little difference. What you have is fine. Once you settle on a specific round then you can fine tune. Accuracy is a different matter.

As an example.... first pic below are two very different rounds-- 55gr at 3240fps and 77gr at 2750fps. With a 2.5in sight over bore and a 50yd zero there isn't a lot of difference out to 200yds.

ps. No need to overthink twist rate. The 55 and 62 grain bullets you're using won't know the difference.

55 & 77



55 & 62

This is why I'm fine with 1/9; it stabilizes the 55gr I shoot just fine, but will do 62gr loads as well. The 1/7 standard twist was to stabilize tracer.

The original AR15 had a 1/14 twist for the 55gr M193 bullet, which permitted the round to tumble upon impact; this gave rise to the stories of its devastating lethality. HOWEVER, accuracy suffered in very cold conditions, so the Army changed the spec to 1/12.

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I haven't found any ammo larger then 62 grain .. actually the ammo selection in the 3 stores I've looked isn't very good or large .. even in the 2 big box gun stores in the area ..

Maybe when it warms up there will be a better selection of ammo .. if that doesn't happen I'll shoot a couple hundred rounds till I find what my AR likes and then buy either a case or 1/2 case of it from some where ..

I see Natchez Shooters Supply has Federal 55 grain for 309.99 with a 10 dollar rebate and a free t-shirt ?? don't know what shipping costs would be to me .. how are they to order from ?? Guess I need to look and see what a case would cost and which are reliable web stores to order from ..

Natchez is fine to deal with, and the case price you noted, along w/ a free T shirt is not a bad deal for bulk 55 grain fmj.

A note about ammo. The bulk 55 grain fmj stuff, as well as the 62 grain green tip, is fine for plinking, and all around use, but it most likely will not give you the best accuracy the rifle is capable of.

Ammo like Federal Gold Match, Black Hills Match, Hornady, ect. will likely prove more accurate, at an increased cost. So when you sight in, if your groups are not as tight as you would like, better ammo is an option. That said, 90% of my AR shooting is with the bulk Federal stuff, as it is cheap, and does what I need for most of my shooting. Depending on shipping, the internet is your friend when looking for ammo, as selection, and usually price, is lots better than shopping locally. Attached is a link that might help.

GunBot 556 rifle ammo

Larry

Thanks Larry for that web site ..

Knew the match grade would be much better if shooting for group size .. I shot on several base rifle teams when I was in the service many years ago .. so I will most likely shoot a little of both kinds .. cheaper for the kids to plink with and match for when I want to see how good I still am .. or for my pleasure .. I know I won't shoot near what I did 45 years ago .. eyes are tired and hands not nearly as calm as when I was younger ..

My wife has said she might like to shoot rife over hand guns due to her carpal tunnel on her right wrist .. which gave me an opening for this my first AR ..

Maybe one of those aftermarket soft rubber pistol grips on the rifle might help increase your wife's comfort level?

Larry

Actually I was looking at those last night on line .. I also like the grip that straightens the grip angle some I would like to see how they would feel .. so will look for one at the range ..

I ordered the MagPul MS4 Gen 2 sling with QD mounts should be here tomorrow as it arrived at the post office an hour ago .. I've always shot a rifle using a sling since I was introduced to competition rifle shooting when I was a teen .. a old leather one I use on my shotgun just would work properly or look right !!

Suppose to be high 60's but windy and rain Friday .. but the range I shoot at has covered shooting pads so might just go ahead and go .. as long as the wind isn't blowing really hard I should be ok sighting it in ..

in the future I can see a drop in straight faced trigger of some quality brand .. but that's down the road a month or two or three .. after some shooting .. and then maybe a scope of some type next spring if Santa is nice to me ..

The stock trigger is probably close to 10 pounds but breaks sharply .. reset is about 1/8 inch and is both audible and has a tactical feel .. I really need to get me a trigger gauge ..

As others above may have eluded to, zero your weapon to what you plan to shoot most, or what you will be shooting in SHTF situation. For me that's 55gr.

Actually, yes, there is a such a thing as overstabilization. However, it's effect is generally not seen at shorter ranges.



What happens when a bullet is overstabilized by a twist faster than it needs is the axis of the bullet does not follow the trajectory line. Meaning the nose point and the center of the base are located on the trajectory line.

Instead, the nose stays in its original plane, keeping its nose up. As range increases, the nose remains pointed upwards, and the bullet strikes with its side, usually the ogive but in severe cases with its entire side, which looks like it is tumbling when it hits paper. It's not tumbling though, just striking side-on.

In addition, the bullet, due to excessive gyroscopic forces, drifts off course.

The chart above is an exaggeration of this effect, but illustrates the point.

Most shooters do not see this because either they are not shooting at ranges where the effect becomes noticeable, or the degrading accuracy is masked by other factors; often the gyroscopic drift is blamed on wind drift. And a dead varmint is a dead varmint, whether hit point on or ogive on.

If you are shooting for maximum accuracy art long range, you do not want a twist faster than what is ideal for your bullet (though there are some exceptions due to slow velocity, like with blackpowder or handgun cartridges). Frankly I prefer a 1:12" twist for .223, but will compromise with as fast as a 1:9". I will not accept a 1:7" for 55 grainers, though they certainly will work OK except at long range where the overstabilization effect starts kicking in. Since the M4 style gun is a carbine and not a long range rifle, this probably makes no practical difference, though, for most shooters.

Have had my new AR-15 for 3 weeks now and have been unable to shoot it yet .. Its the longest I have gone with out firing a new gun

20 days in March it has rained here and the out door range is a muddy mess .. one entrance is closed because of water .. a lake of water on the 200 and 500 yard ranges and now its rained 2 days in April.. more expected this week ..

Anyone else having trouble getting to the outdoor range in their area ??

Really haven't had any issues, even though we're a good 9" above average. After 5+ years of drought that's a good thing. About the only thing that's been messed up is the freshwater fishing. Rivers have been muddy and running high.

Mostly been plinking and shooting some guns that have been quiet for 20+ years. Starting to do some serious load dev work with 62 and 69gr.

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Peace was my Profession

I learn so dang much on this forum. Thanks guys!

I have found that my Sport I (with the 1:8 5R barrel) likes a 69 gr. bullet. PPU 69 gr. bullets seem to get the best groups at 100 yards. PMC X-TAC 55 gr. seems to shoot better than any other 55 gr. in my Sport I.
My results may vary from others with the same AR.

You have to be careful slinging up with an AR unless it is set up for it like a match rifle. Using a tight sling will many times throw your shots off, you did not mention what type of AR you got but if a carbine shoot an enjoy as a carbine.

Sorry thought I had said which model I had gotten .. I bought this model .. 311041LE Smith & Wesson MagPul Tactical M&P-15T 5.56mm

#https://www.sportsmansoutdoorsuperst...-DEFAULT-l.jpg

After 20 days of rain in March and now 4 days in April . is it going to give us a break so everything will dry out ... Illinois River at flood stage and some sand bagging around the downtown area of Peoria as flooding is occurring .. we need a week to dry out .. the range is flooded with standing water .. had hail just 30 minutes ago .. over 1/2 inch of rain so far today with rain continuing thru tomorrow ..