-
Having trouble using the site?
Contact support
Newbie question AR15
- Thread starter bdn6465
- Start date
Barel
BCG
Rail
Trigger
These can all adjust depending if you buy shitty components. Just stick with Colt, LMT, BCM....top tier stuff and you wont have issues.
PB
BCG
Rail
Trigger
These can all adjust depending if you buy shitty components. Just stick with Colt, LMT, BCM....top tier stuff and you wont have issues.
PB
- Nov 3, 2010
- 9,720
- 20,452
You left out the most important component: the shooter. Seriously...put a $700 AR into the hands of a guy who has his fundamentals locked in and he will outshoot the "Geirdos" who think they "buy" their way into consistently accurate shooting.
But..having said that.
Most important components are not on your list:
Barrel (free float)
Trigger group.
Great bipod (don't go cheap)
Optic.
Thanks guys. I bought a used factory Rock River Arms with unknown round count and have since shot easily 2k rounds more. If I shot rounds at 100 yard at a 3 inch bull eye using a 16x scope (I know, bad eye sight), approximately 75-80% would be in the center 2 inch group with the rest scattering around the outer 3rd. Is it time to change the barrel?
That's 2 MOA at 100 yards which is considered more than "good enough" for a stock AR. Better quality ammo may help. But 2" is fine and dandy with that AR.
Good grief, those are some of the best groups I’ve seen with that kind of ammo. Give your barrel and bolt carrier a good cleaning and get some quality ammo; match grade stuff from Federal, Hornady, or Black Hills. Then you will see what it will really do.
Do you know the twist rate of the barrel? If it’s a 1 in 7 then go for 75 or 77 grain match ammo. If it’s a 1 in 9 then don’t go over 69 grains; try something between 55 to 69.
Do you know the twist rate of the barrel? If it’s a 1 in 7 then go for 75 or 77 grain match ammo. If it’s a 1 in 9 then don’t go over 69 grains; try something between 55 to 69.
The Essentials of an Accurate AR-15
Without making this overly complicated, you need three basic components for a semi-automatic AR-15 to produce its best mechanical accuracy (technically, precision): a match-grade barrel, a quality free-float handguard and match-grade ammunition, preferably hand-loads tuned for your barrel. (The free-float handguard doesn’t improve the accuracy of the barrel per se, it simply prevents any outside influence from detracting from the accuracy of the barrel.) Anything after that will not immensely improve the mechanical accuracy of the semi-automatic AR-15, but several things can help you, the shooter, shoot to the level of the intrinsic accuracy of your semi-automatic precision AR-15.
While there are certainly gifted individuals among us that can do amazing things with iron sights, most of us will benefit from using a quality, high-magnification scope to achieve the highest level of accuracy from a precision AR-15. In order to hit the exact same spot on the target every time, you have to be able to see that you are holding on the exact same spot every time. It’s also important for the scope to be mounted at the proper height and at the correct eye-relief for the particular scope. One of the most common errors I see with scopes mounted on AR-15s is the scope not being mounted far enough forward for its eye-relief. Also, in order to maintain that exact hold throughout the trigger pull, it helps not to be fighting a heavy, gritty, stock trigger. There are a variety of aftermarket triggers now on the market for both standard size trigger pins and the larger Colt trigger pins. Personal preference will definitely play a role in trigger selection. Among the two-stage triggers, I’ve found the Geissele High Speed National Match triggers to be the smoothest, lightest, most consistent and most reliable. For single-stage triggers, it’s hard to beat the Geissele SSP and the JP Enterprise Fire Control System. Keep in mind that the JP trigger does require fitting and adjustment.
Following the scope and trigger selection, some shooters will find that items like aftermarket grips and stocks will help them achieve a better “fit” with their AR-15. (Shooters don’t all come in the exact same size and shape, don't ya know!) Once you’ve put your precision rig together, you have to find a match-grade factory load that your barrel “likes” or better yet, develop a match-grade handload for it.
A semi-automatic AR-15 is not going to shoot as accurately as a precision bolt-gun, but today’s precision AR-15s are capable of a level of accuracy that is truly outstanding for a semi-automatic rifle. The 10-shot group pictured below was fired from one of my Krieger barreled semi-automatic AR-15s from a bench-rest at a distance of 100 yards. The barrel has a 1:7.7” twist. I used Sierra 55 grain BlitzKings that were hand-loaded on a Dillon XL-650 progressive press. The load was developed using my Accuracy Node Detection Technique. The group has an extreme spread of 0.452”.
...
Without making this overly complicated, you need three basic components for a semi-automatic AR-15 to produce its best mechanical accuracy (technically, precision): a match-grade barrel, a quality free-float handguard and match-grade ammunition, preferably hand-loads tuned for your barrel. (The free-float handguard doesn’t improve the accuracy of the barrel per se, it simply prevents any outside influence from detracting from the accuracy of the barrel.) Anything after that will not immensely improve the mechanical accuracy of the semi-automatic AR-15, but several things can help you, the shooter, shoot to the level of the intrinsic accuracy of your semi-automatic precision AR-15.
While there are certainly gifted individuals among us that can do amazing things with iron sights, most of us will benefit from using a quality, high-magnification scope to achieve the highest level of accuracy from a precision AR-15. In order to hit the exact same spot on the target every time, you have to be able to see that you are holding on the exact same spot every time. It’s also important for the scope to be mounted at the proper height and at the correct eye-relief for the particular scope. One of the most common errors I see with scopes mounted on AR-15s is the scope not being mounted far enough forward for its eye-relief. Also, in order to maintain that exact hold throughout the trigger pull, it helps not to be fighting a heavy, gritty, stock trigger. There are a variety of aftermarket triggers now on the market for both standard size trigger pins and the larger Colt trigger pins. Personal preference will definitely play a role in trigger selection. Among the two-stage triggers, I’ve found the Geissele High Speed National Match triggers to be the smoothest, lightest, most consistent and most reliable. For single-stage triggers, it’s hard to beat the Geissele SSP and the JP Enterprise Fire Control System. Keep in mind that the JP trigger does require fitting and adjustment.
Following the scope and trigger selection, some shooters will find that items like aftermarket grips and stocks will help them achieve a better “fit” with their AR-15. (Shooters don’t all come in the exact same size and shape, don't ya know!) Once you’ve put your precision rig together, you have to find a match-grade factory load that your barrel “likes” or better yet, develop a match-grade handload for it.
A semi-automatic AR-15 is not going to shoot as accurately as a precision bolt-gun, but today’s precision AR-15s are capable of a level of accuracy that is truly outstanding for a semi-automatic rifle. The 10-shot group pictured below was fired from one of my Krieger barreled semi-automatic AR-15s from a bench-rest at a distance of 100 yards. The barrel has a 1:7.7” twist. I used Sierra 55 grain BlitzKings that were hand-loaded on a Dillon XL-650 progressive press. The load was developed using my Accuracy Node Detection Technique. The group has an extreme spread of 0.452”.
...
Last edited:
I consider the barrel and trigger to be the key accuracy features on AR's, and in fact, on all rifles.
I prefer to buy complete Uppers, for reasons of simplicity and reliability.
I also have a mental block about triggers; I like 2 stage triggers for stationary shooting. For action shooting a smooth single stage with a quick, short reset makes better sense.
Molon nailed it.
Greg
I prefer to buy complete Uppers, for reasons of simplicity and reliability.
I also have a mental block about triggers; I like 2 stage triggers for stationary shooting. For action shooting a smooth single stage with a quick, short reset makes better sense.
Molon nailed it.
Greg
Get yourself a box or 2 (when its actually available) of some quality 75-77gr match grade ammo like Federal, Norma or Hornady and get a proper baseline of the rifle's capability. The steel cased stuff you are shooting isn't going to group better than 2-3" @ 100yd out of any rifle, and possibly even worse than that so you aren't currently getting any good idea of its potential.
If you're still not happy with those groups then I would recommend barrel upgrade and free-float done at the same time. The handguard, delta-ring assembly and FSB all have to come off to change the barrel so you might as well do the handguard too.
When you're reassembling (if doing the work yourself) it would be a really good idea to have some ft-lb and in-lb torque wrenches available for the barrel nut, low-pro gas block and handguard screws. Over/under-torquing these can have negative effects on accuracy as well.
Thank you for your advice. Yeah i have a bunch of Black Hills OTM and FGMM SMK that I was saving for my Tikka T3 Tactical. Maybe I can use some of it to baseline my AR. Again, thank you all who helped. Great place to seek knowledge...
BTW, what is an FSB in your post?
No, I don't know the twist rate. I bought this rifle when I first starting out so I didn't know whats what. I still don't. LOL...Is there a way to tell the twist rate? I know some manufacturers engraved it on the barrel and some don't.
FSB = front sight base.
The twist rate is normally on the barrel, but you’ll probably have to remove the hand guard. If you run a tight cleaning brush down the barrel and mark the rod so as to measure the distance it goes down the barrel and the number of revolutions, you can can measure the twist rate close enough. In fact, just measure off 7.5” and 9” on the rod, push it down the barrel and see where you are when the rod makes one complete revolution. It should be close enough. I suppose it could be a 1 in 8 twist too. Or just call rock river and give them the SN and see if they know.
The twist rate is normally on the barrel, but you’ll probably have to remove the hand guard. If you run a tight cleaning brush down the barrel and mark the rod so as to measure the distance it goes down the barrel and the number of revolutions, you can can measure the twist rate close enough. In fact, just measure off 7.5” and 9” on the rod, push it down the barrel and see where you are when the rod makes one complete revolution. It should be close enough. I suppose it could be a 1 in 8 twist too. Or just call rock river and give them the SN and see if they know.
Accuracy is about eliminating variables. The more you can eliminate the less you have to deal with or adjust for. YOU are the greatest asset to accuracy. I'll just say "Fundamentals" and move on. But there's a lot to that so don't discredit it, it's just too much to go into here. So hardware-wise...
Your barrel is number one, it's worth probably 90-95% of your accuracy right up front. Good barrels will come with or offer to supply a headspaced bolt. Go ahead and do this if you're building the rifle. Krieger and some other high end mfg.'s will use the JP bolts. I'll get back to those. The barrel also adds some to the reliability of the system, but this depends solely on the gas port and exactly where it's drilled and the dia. of that journal.
A FF tube (more common than not nowadays) will shave about ..25-.5MOA IIRC and a fixed stock will do about the same vs. a loose collapsible one. A SOPMOD or B5 stock is an exception (there may be others but those are what I use, KAC uses 'em and they work as well as a fixed stock --they don't move and have a great cheekweld).
When barreling the action, facing the upper so it's even and bedding the barrel to the upper I understand can reduce MOA 1/4 or more, depending on how loose it was to start with. Loctite 620 will, I think, turn your upper/barrel into basically one piece and rebarreling a rifle will entail buying a new upper, but you'll have the peace of mind knowing that ain't moving. If the barrel is loose, you can only expect casual accuracy at best.
A 2 stage trigger won't shave MOA or make you more accurate, it can just make it easier. I can and have shot within the limitation of an M4 using the stock shit trigger they come with and a Geissele wouldn't have made a difference, though it would've sped things up and made it easier. In other words, it doesn't make the rifle more accurate but it can make you more accurate if that makes sense. Reduced lock time MAY play a role but I'm sure it's so miniscule it's not worth measuring, not in a typical AR anyway.
BCG does not add accuracy, it adds reliability. In fact, how your barrel is worth all the accuracy, your BCG, with all the moving parts in the weapon, is worth all your reliability. JP FMOS is the king of the hill here. Now if your barrel came with the JP bolt, you only need the carrier. These things are so slick they'll run reliably dirty and totally dry with a suppressor spraying layers of shit all over the action (it's mind blowing actually). If the barrel doesn't come with the JP bolt, I wouldn't worry about headspace issues with a high end barrel and I'd get the JP bolt and carrier and use that.
According to Krieger and Lilja, both breaking in a barrel properly and using clamp on gas blocks is ideal. Lilja tells you how to break it in, Krieger will tell you in detail why and it has little to do with the barrel and more to do with the chamber, throat and leade. Anyway, they claim a reduction in groups when done this way. They claim pinning a gas block creates a bump in the system that fucks up barrel harmonics and reduces accuracy, however, having seen clamp ons and even set screw gas blocks take a shit and fly down range, I pin mine. I prefer the Bombproof Geissele Super Gas Block, easy to install.
If you do it right it'll be accurate AND reliable AND you won't need to fuck with all these adj. gas blocks others have to fuck with. I do have a Switchblock barrel I got for on sale cheap but to be honest, I don't know what the fuck I'm gonna do with it.
Oh, and if you want an accurate and reliable SBR, check out Noveske for their barrels, they've been my goto for SBR barrels for years now. Never had a problem.
Hope that helps.
Your barrel is number one, it's worth probably 90-95% of your accuracy right up front. Good barrels will come with or offer to supply a headspaced bolt. Go ahead and do this if you're building the rifle. Krieger and some other high end mfg.'s will use the JP bolts. I'll get back to those. The barrel also adds some to the reliability of the system, but this depends solely on the gas port and exactly where it's drilled and the dia. of that journal.
A FF tube (more common than not nowadays) will shave about ..25-.5MOA IIRC and a fixed stock will do about the same vs. a loose collapsible one. A SOPMOD or B5 stock is an exception (there may be others but those are what I use, KAC uses 'em and they work as well as a fixed stock --they don't move and have a great cheekweld).
When barreling the action, facing the upper so it's even and bedding the barrel to the upper I understand can reduce MOA 1/4 or more, depending on how loose it was to start with. Loctite 620 will, I think, turn your upper/barrel into basically one piece and rebarreling a rifle will entail buying a new upper, but you'll have the peace of mind knowing that ain't moving. If the barrel is loose, you can only expect casual accuracy at best.
A 2 stage trigger won't shave MOA or make you more accurate, it can just make it easier. I can and have shot within the limitation of an M4 using the stock shit trigger they come with and a Geissele wouldn't have made a difference, though it would've sped things up and made it easier. In other words, it doesn't make the rifle more accurate but it can make you more accurate if that makes sense. Reduced lock time MAY play a role but I'm sure it's so miniscule it's not worth measuring, not in a typical AR anyway.
BCG does not add accuracy, it adds reliability. In fact, how your barrel is worth all the accuracy, your BCG, with all the moving parts in the weapon, is worth all your reliability. JP FMOS is the king of the hill here. Now if your barrel came with the JP bolt, you only need the carrier. These things are so slick they'll run reliably dirty and totally dry with a suppressor spraying layers of shit all over the action (it's mind blowing actually). If the barrel doesn't come with the JP bolt, I wouldn't worry about headspace issues with a high end barrel and I'd get the JP bolt and carrier and use that.
According to Krieger and Lilja, both breaking in a barrel properly and using clamp on gas blocks is ideal. Lilja tells you how to break it in, Krieger will tell you in detail why and it has little to do with the barrel and more to do with the chamber, throat and leade. Anyway, they claim a reduction in groups when done this way. They claim pinning a gas block creates a bump in the system that fucks up barrel harmonics and reduces accuracy, however, having seen clamp ons and even set screw gas blocks take a shit and fly down range, I pin mine. I prefer the Bombproof Geissele Super Gas Block, easy to install.
If you do it right it'll be accurate AND reliable AND you won't need to fuck with all these adj. gas blocks others have to fuck with. I do have a Switchblock barrel I got for on sale cheap but to be honest, I don't know what the fuck I'm gonna do with it.
Oh, and if you want an accurate and reliable SBR, check out Noveske for their barrels, they've been my goto for SBR barrels for years now. Never had a problem.
Hope that helps.
As mentioned above it is the Front Sight Base. Here you go and tell us you have noob questions and I throw an acronym at you without explanation, so that's my bad.
If it's not marked, try using a cleaning rod with a brush attached. Make a mark somewhere on the rod while the brush is in the barrel and another mark on the rod at the muzzle. When the rod turns 360deg. (the first mark you made will be TDC again) make a second mark at the muzzle. Pull it out and measure between the two marks you made at the muzzle and that'll be your twist rate. If it comes out nine inches, then it's 1:9 or one turn in nine inches.
Barrel SHOULD have it on there, may be under handguard, may just be one number like "7" and nothing else, may be a decimal or a fraction but it's usually on there. Could be top, could be bottom but it's almost always after the FSB or gas block.
Oh, and "FF" means free floating in case that wasn't clear.
I think you'll find that knowledgeable people will be more inclined to help a "newbie" when he/she genuinely asks a question in good faith (as you did); as opposed to showing up in a technical forum regurgitating false information, that they saw some Internet Commando post, as if it's a fact and trying to pretend that they're an expert on a topic that they clearly know jack-shit about.
parts are nice but more likely than not almost any of them would do you well enough you the shooter would be the weakest link , not saying the gun could not have a problem anyone can make a p.o.s from time to time . But your skills with that gun seem like they would matter more than a few parts . I could be totally wrong but some of the best shooters in the world never had namebrand fancy parts just bone stock what ever brand they could afford .
I'm guessing that if he's truly shooting 2-3 MOA with shitty steel-case ammo then his rifle would likely do decently with good ammo and he is also likely doing his part behind the rifle. That crap ammo will make a pretty good rifle shoot some ugly groups.
My 16" long, 1:7" twist Lightweight AR barrel shoots IMI 77gr very nicely, but I suspect that a 1:8" twist wouldn't work for that bullet weight at that short length.
It will shoot nicely in my 24" long, 1:8" twist barrels.
The crossover point is somewhere between 16" and 24" in length, but since those are the only barrel lengths I have; I can't tell you where that crossover occurs.
Greg
It will shoot nicely in my 24" long, 1:8" twist barrels.
The crossover point is somewhere between 16" and 24" in length, but since those are the only barrel lengths I have; I can't tell you where that crossover occurs.
Greg
I can't specifically comment on the IMI 77gr but I shoot 77gr FGMM, Norma Match and Hornady Match out of my 1:8 twist 18" with great results. Barrel is a WOA 18" SPR profile with .223 Wylde chamber.
Try that good ammo and see how she shoots. ARs will shoot good with quality barrels, parts and ammo. This is 4 shots at 500 yds. And before people get smarty pantsy, shot number 5 went onto the popper.
- Nov 3, 2010
- 9,720
- 20,452
I only hope my new barrel shoots that good. Will give me something to practice towards
It’s largely Internet Commando myth that bullet stability increases with increasing barrel length. Technically, the gyroscopic stability factor does increase with increased barrel length, however the amount that it increases is miniscule and lost in the noise of other variables.
As an example, the 55 grain bullet in M193 will have a gyroscopic stability factor of approximately 4.25 when fired from a 14.5” Colt M4 barrel. When the same M193 round is fired from the 5.75” longer barrel of the 20” Colt A2 barrel, the gyroscopic stability factor of the 55 grain bullet only increases to approximately 4.27.
While the increased RPM due to the faster velocity will act to increase the bullet stability, the increased velocity also “increases the force applied to the nose of the bullet at the center of pressure and strengthens the overturning aerodynamic torque which actually makes the bullet less stable.”*
* From Applied Ballistcs For Long-Range Shooting by Bryan Litz
The IMI 77 grain Razor Core shoots great from my 20" Lothar Walther barrel which has a 1:8" twist.
....
Last edited:
Thank you for explaining that; I'm still learning, and actual facts make the difference.
Anecdotal info like this helps me form my pattern of understanding about technical subjects. They form the necessary balance offsetting entrenched "common knowledge". Thank you as well.
Greg
Anecdotal info like this helps me form my pattern of understanding about technical subjects. They form the necessary balance offsetting entrenched "common knowledge". Thank you as well.
Greg
I am in the process of discovering the principles of an accurate AR rifle, by building one. So far I have not achieved anything better than 1.5MOA from either a STAG15 24" VARMINT upper, or from rebarreling that upper with a Proof Research REECE profile. Both were free float. I've trued the upper with the Wheeler kit, and Locktite 620'd the STAG barrel to no gain. I've tried dozens of MILSURP loads, as well as Black Hills Match and Hornady Match and plenty of my own handloads (all with LC81 brass. CFE223 powder, and CCI SR primers.) I've tried all the usual accuracy loading techniques for bolt guns (neck turning, seating depth, etc. and continue to get ES: 150 or so, but accuracy never below 1.0 MOA. Latest upgrade is a Trigger Tech single stage which is set to feel exactly like my 1911 match pistol. Again no gain, but boy howdy does it feel nice!
I've run Audette and Shatterly tests - results have not show correlation to 100 yard accuracy.
My ultimate goal is to use the rifle for ground squirrels (1"x0.5" vital zone) to … well my Savage 10FPC in 204 (0.3MOA) gets me to 500 yds on them, so in an ideal world the AR would achieve the same effective range.
A secondary purpose of this build is to inform an article I will write into my notebook on the subject. You can see I'm quite deep into the physics of interior ballistics, so any insight is very welcome.
Could I ask you to expand on your "Accuracy Node Detection Technique" please?
Thanks!
My notebook: http://SnellsNotebook.us
Couple things jump out at me after a quick scan of your post and "notebook"
1. Your barrel nut torque is pretty high. I snug/loosen the nut twice and torque to 40 ft-lb on the 3rd.
2. You mention max pressure loads which could be an issue. Might get better precision if you back down a little bit. I find that my 77gr loads lose precision at the top of the load chart.
3. Maybe a headspace issue. Did your barrel come with a matched bolt? Many barrel makers offer this as an option.
4. Make sure your gas block set screws aren't over tightened. I use 25 in-lb and red loctite. Never had an issue.
5. Make sure your gas block isn't touching the inside of the freefloat and that the rail retaining screws are torqued to manufacturers spec.
Similar threads
