AR-15 Information and Troubleshooting
Rules for Reloading for Flawless Feeding and Function of all AR-15 cartridges (including
the .223 Rem, the 20 Practical, the 6mmAR, etc.).
Almost without exception, most of the AR-15 feeding and function issues people call in on relate to errors or problems with reloading. Here are some basic rules for reloading for flawless feeding and function:
Rule #1 - Bump The Shoulder of Re-sized Cases .003” - .005” - Generally speaking, when you re-size cases when reloading for a semi auto AR-15 you need to leave “wiggle room” to assure that the re-sized cases will feed and chamber easily. Full length re-sizing of fired cases is required. In addition, you need to bump the shoulder of the fired cases between .003” - .005” when resizing, and you need to make sure when you set up your re-size die that it does this. A lot of shooters (particularly bolt gun shooters who are not familiar with semi auto AR-15’s) violate this rule and only bump the shoulder .001” - .0015”, figuring they will keep all tolerances very close, hoping for better accuracy, only to find out they will get rounds that will not chamber properly and will jam in the gun (and boy will they jam). A shoulder bump of .003” is the absolute minimum for AR-15 cases (not just the 6mm's but the .223 Rem., etc.). If you don’t have a way to measure your shoulder bump, my suggestion is to go out and buy the Hornady Lock-N-Load Headspace Gauge kit (about $35 – do an internet search and it will pop up on Amazon.com, Midway USA, etc.) and use the proper bushing in the kit to measure your shoulder bump (fired cases vs re-sized cases). For the 6mmAR and Turbo cartridges you use the .350 bushing in the kit. You use the kit to set up your re-size die properly (i.e. measuring fired cases vs re-sized cases). The kit comes with 5 bushings that you can use for just about all other cases one might also reload for. Note: It is best to measure the headspace of fired cases with the primer removed from the case.
Rule #2 – Load Magazine Feed Bullets Less Than The OAL Where They Hit The Lands - You need to know at what OAL your bullets hit the lands and keep your cartridge OAL less than that for magazine feeding. If you just load bullets at maximum magazine length thinking they should feed in the rifle, you can be absolutely wrong! Especially with the 6mm bullet lineup, there is a huge difference in some of the ogives and bullet tips, some will hit the lands at a much longer OAL than magazine length and some much shorter than maximum magazine length. If you take a cartridge with a bullet that hits the lands when loaded at 2.185” OAL and load it at 2.260” (which is generally close to maximum magazine length in an AR-15), the bullet will be .075” in the lands and the cartridge will not likely feed and chamber reliably in and AR-15. If you do not have an accurate way to measure this, we sell the modified case ($12.50) that fits on the end of the Hornady Lock-N-Load OAL Tool (about $30 - do an internet search for the tool and it will pop up on Amazon.com, Midway USA, etc.). For an AR-15 you use the straight tool (i.e. the one for bolt guns, not the ones they advertise for semi-autos) because if you take you upper off the lower and pull out the carrier, you have a straight run through the back of the receiver to use the straight tool.
Rule #3 – Bullet Tips Vary So Leave A Margin Of Error Especially For Loads At Maximum Magazine Length - Bullet tips vary, even in the same lot of bullets, so it is always advisable to leave a margin for error when you determine the OAL for loading bullets at maximum magazine length. If a cartridge is binding up in the magazine because you loaded it to long for it to freely move up and through a magazine, you are going to have feeding problems.
How To Lube Your AR-15 (Very Important)!
People speak of running AR-15’s “wet” but this is not the way to go at all. An AR has gas blow back and gas with particulate matter gets back into the inside of the upper receiver, the bolt carrier, etc. Having a wet sloppy mess of oil and grease in there does nothing but provide a trap for a big grungy mess to form and clog things up.
The right type of lubrication needs only be applied where there is metal to metal contact of moving parts - any more is a potential cause for problems. You don't want gobs of oil and grease shooting and squirting all around inside your rifle as it cycles, sending lube into places where it does not belong (i.e. down in the magazines, on the bullets themselves, up inside the chamber, back into the buffer tube assembly).
Would you indiscriminantly hose down the inside of your car's engine compartment and the drive train underneath your car with lube and oil? No!
On lubrication, about 95% of all "gun" lubricants out there are not appropriate for an AR. For the bolt lugs in particular you need a very high viscosity sticky lubricant because the lugs are a "severe duty" application in that they open fast under pressure and get very hard use otherwise. Most greases are no good because they don't stay around. The best lubricant I have found is Phil Wood Tenacious Oil (it's like a sticky 90 wt. gear oil) and you can buy it for $8 or so at your local bicycle shop or on the internet in its own applicator bottle. I have built up a lot of AR's over the years and seen others come back for re-barreling or other work. Some have an enormous amount of bolt wear (and a corresponding dramatic increase in head space) because inadequate lubricant was used. The owners thought they were using a good product, but it was not. A lot of the favorites are no good either (and I am not going to name names).
Some parts not to lubricate at all: 1. The firing pin (don't need anything to impede the pin making a good strike on the primer); and 2. The buffer or the buffer spring assembly (unless you want your rifle to possibly malfunction and short stroke); 3. If you are going to be shooting in very cold weather, keep the lubricant off the lateral riding surfaces on the outside of your bolt carrier or it can slow the carrier down enough so the rifle will short stroke. Above about 20 degrees F, that's not an issue typically.
The areas that always need it: 1. The rear of the bolt lugs (severe duty – must do, but only need a little bit on the back of each lug); 2. The cam pin (another severe duty place, put around the pin just below the head of the pin); 3. The very back of the bolt behind the gas rings (the .250” diameter stem) where it rides in and out of the carrier; and 4. The gas rings; and 5. The lateral riding surfaces on the outside of the bolt carrier, except in very cold weather (like below 20 degrees Fahrenheit) where high viscosity lube can slow down the carrier and possibly cause the rifle to short stroke).
Primers That Are Appropriate for AR-15 Use
The design of an AR-15 makes it more susceptible to piercing primers or a slam fire than some other rifles. The use of an improper primer in an AR-15 is almost an invitation for a primer piercing and other related primer problems. It is essential that primers are used that can withstand the rigors of AR-15 shooting. Some of the primers that we have found are appropriate for shooting in AR-15's are listed below. For accuracy work we recommend CCI BR-4 primers, Rem 7.5 BR primers, Wolf Small Rifle Magnum primers (these are not really a magnum primers and Wolf kind of mislabeled these only becuase the cup metal makes it tough enough for use in magnums and AR-15's too) and the older Winchester Small Rifle Primers (the silver plated ones that came in the white boxes/sleeves only). In the magnum primer category of AR-15 appropriate primers: CCI #41, CCI #450, Wolf Small Rifle .223 primer (not to be confused with the inappropriate Wolf standard small rifle primers noted below or Wolf the small rifle magnum primer noted above).
The small rifle primers that we considered as not generally appropriate for use in AR-15's include CCI #400 primers, Fed 205 primers, Fed 205M primers, Rem 6.5 primers and the newer Winchester Small Rifle Primers (brass colored that come in blue boxes/sleeves), and the Wolf Standard Small Rifle primers (a copper colored primers).
Barrel Break-In and General Day to Day Cleaning of the Bore
I don't get carried away with lengthy shot and clean routines for barrel break-in as I feel that is excessive and counter productive for a hand lapped premium barrel. As far as barrel break-in, usually you should not need very much with a premium hand lapped barrel like you have with an AR-X upper. Mostly new barrel break-in with these barrels is just getting the barrel to the point it does not pick up any copper or unusual fouling. Usually when uppers are test fired they are cleaned and then inspected with a bore scope. Some of the barrels pick up a little bit of copper or fouling (but not much) in the forward two thirds of the barrel, some have nothing after just the test firing and cleaning. If there is coppering, this usually disappears very quickly after just a couple cleanings. For break in I usually shoot 5 shots and clean the barrel, shoot another 5 shots and clean it, then shoot 10 shots and clean it, and then just go do whatever shooting I normally would, and clean as I normally do (for me, I usually clean at home after each match or shooting session). For cleaning of the bore, I typically use Shooters Choice, run a few wet patches through the bore, then brush the bore a little (not much) with a bronze bore brush liberally coated with Shooters Choice, then run a couple more wet patches through the bore, then wait a couple minutes and run a couple dry patches down the bore and that's it. I usually don't use copper solvents. The above cleaning instructions are just for the bore of the barrel and not for the rest of your AR-15.
How To Extract A Jammed Round From Your Chamber
In the unlikely event you have a situation where you have a round jammed in the chamber (like where a round has been loaded too long or not re-sized correctly, etc.) and you cannot easily get the round out of the chamber, perhaps the best way to clear it is to put the muzzle of the rifle straight up in the air (being careful to keep the rifle always pointed in a safe manner away from anyone or anything, and keeping anything and everything away from the muzzle since there is a live round in the chamber), lift the butt of the rifle about 6” off the ground and while pulling on the regular charging handle (not a side charging handle), hit the butt of the rifle on the ground firmly. The combination of the weight of the bolt carrier, coupled with the sudden stop of the rifle when it hits the ground, coupled with you hanging on the charging handle, will usually clear the rifle. It is best not use a screwdriver or other implement to try to pry back the carrier, and do not hammer on a side charging handle, since both of these options may cause damage to your rifle. Just a side note, for many shooters the first instinct is to put the safety on when you have a jam as described above, but be aware that with some triggers, if the hammer is partially down, and you put the safety on, it can then prevent the hammer (and bolt carrier) from traveling backwards as is needed to extract the round out of the chamber (Armalite two stage match trigger, and some others). I am not going to advise people to not put the safety on, but with some triggers, you cannot have it on while you try to clear the rifle because it won’t let the hammer on some triggers (or the carrier) come backwards.
Bullet OAL’s – You Must Measure Your Own
Bullet OAL's are always dependent upon your chamber and the lot of bullets you have. You must (I stress the word MUST) measure your own bullets in your chamber. Any OAL on the website is just to give a general idea of where things might sit (they were measurements with the bullets I had in hand in my rifle) and it would be best to use your own measurements with the bullets you have in hand in your rifle. I have seen OAL's with the 6mm 105 VLD's vary up to .060" depending on the lot of bullets. Bullets from lot to lot do vary considerably so don’t put too much faith or stock in the bullet OAL’s on the website, because the OAL at which your bullets hit the lands may be a good bit shorter or longer depending on what bullets you are using and/or what lot of bullets you have.
Side Charging Handle Upper Receivers & Out of Spec Buffer Assemblies
If the upper you purchased from us has a side charging handle, be aware this was designed and set up based upon the use of a standard in spec. AR-15 buffer and buffer tube assembly, but it should always be checked with the lower you intend to use to make sure your buffer assembly does not allow the bolt carrier to travel back too far so as to permit the side charging handle to hit the back of the slot for it in the receiver. Some after market stocks with after market buffer tube assemblies may not be dimensionally correct and may allow the bolt carrier assembly to travel back excessively so that the side charging handle will hit the back of the slot in the upper receiver (if this happens this is a problem with your buffer assembly – we don’t see this very often but it was always with after market buffer assemblies that are not to proper specs.). This must be corrected before you use such a buffer assembly or you can cause damage to your rifle. A quick fix, if you have such a buffer assembly is to use one or more quarters (coins) as shims in the back of the buffer tube (behind the buffer spring) to build it up to the point where when you pull back your bolt carrier all the way and it bottoms out, the bolt is past the bolt stop, but not so far that the side charging handle is hitting the back of the slot in the upper receiver.
The Side Charging Handle – Don’t Hammer On It!
A side charging handle is also not meant to be hammered on as a forward assist or backwards to help clear a stubborn jam or problem (like with a round that was incorrectly resized or is loaded too long for the chamber and won’t chamber properly, etc.). If a round does not chamber properly or you have a jam that need to be cleared, the answer is not to take a hammer to the side charging handle to try to hammer the round in or out of the chamber. See also the topic above on how to extract a jammed round from your rifle.
What About Using A Carrier Weight System? Not A Panacea!
I do not recommend using a carrier weight system with the uppers we sell. A carrier weight system adds weight to the carrier thereby assisting in the delay and slow down of carrier cycling. A carrier weight system is not a universal solution that makes all AR-15’s run better. A carrier weight system is typically a good retrofit solution for a factory type AR-15 that has a gas system where the barrel is over ported and the rifle cycles too early, fast and hard. If the gas system for the rifle is properly ported for its actual and intended use, the carrier weight system can actually be the cause of function and feeding problems (because it makes things run slower and more anemic than they should). We work very hard to assure that the gas porting of our uppers is appropriate for the intended uses. From that perspective, you can expect that your upper will be properly ported, and that the addition of a carrier weight system may only put things out of balance and cause issues that would not exist but for the addition of a carrier weight system.
We set up our uppers to work best with the standard weight carriers and standard buffer and buffer tube assemblies.
For those that do single round loading (like high power shooters at the 600 yard line) where you flick a round up in the chamber and then hit the bolt release, the extra weight in the carrier from a carrier weight system just adds a lot more weight and momentum to come flying forward and have to abruptly stop (heavier is not the way to go here, we’re not trying to hammer the round in the chamber).
After Market Special Buffers – Beware!
We set up our uppers to be in balance and to work best with the standard weight carriers and standard buffer and buffer tube assemblies. The uppers are typically in balance and work best with these standard parts. Adding extra heavy buffers or special hydraulic buffers thinking you are going to improve the function of your rifle may have the exact reverse effect. Typically the after market special buffers are made for problem applications (i.e. like AR-15 carbines or pistols) where there is an over cycling problem that needs to be addressed to make the firearm function best. Putting them into your rifle (especially if it is cycling and functioning correctly already) may only throw the function and cycling of the rifle out of balance.
Do Not Grease or Oil Buffer Assemblies To Stop The “Boing” Sound
First off, AR-15 buffer systems were never made to run with oil, grease or lubricant on them (yes dry is the way to go for the buffer, the buffer spring and the inside of the buffer tube). If you add lubricant in there to stop the “boing” sound you will likely change how your rifle cycles and that may cause it to malfunction (i.e. heavy oil or grease in the buffer assembly can cause things to slow down so the rifle short strokes and/or will not cycle properly).
Let me just say this. If you have an AR-15 rifle that has a gas system that's on the verge of being over ported (as many AR's are) you can get away with doing a lot of things and it won't cause a malfunction because your rifle cycles hard enough it will overcome gobs of lube in the buffer tube, grunge and excess lubricant throughout the rifle, etc. (i.e. a military type porting and function set up is like that - it functions no matter what, but top accuracy is not so much the issue there). The downside of that over porting can be a rifle that cycles harder than it needs to, a rifle that may have accuracy issues or just be a little finicky accuracy wise, rifles that people feel need Tubb's Carrier Weight System to slow things down and resolve issues, etc.
If you are going for top accuracy, especially with match and varmint rifle uppers and uppers with longer barrels (because bigger and longer barrels change the dynamics of things - bullet in the bore longer - gas system under pressure longer, etc.), you need to try to tune things to the optimum, and that means everything being in balance (it's all one system including the buffer system, change the dynamics in one place you can throw things out of balance elsewhere - maybe it will be function - maybe it will be accuracy - maybe it will be finicky accuracy wise - maybe you won't notice anything). So then you get into trying to strike the balance for the optimum accuracy and function (both at once) of the rifle.
The true accuracy tuned AR-15 precision shooting rifle may not allow you to glob any old grease or lubricant with unspecified viscosity and properties into the buffer system and permit it to function 100% and be accurate - why should it - the buffer system wasn't designed for that in the first place, so don’t do it!
Bolt Release Extensions – Avoid Them Like The Plague!
There are some add-on extended bolt releases on the market that are sold and allow you to put them on your rifle so you can actuate the bolt release by pushing a lever or button (usually through the trigger guard). I can only say that most of these do nothing but cause problems with the functioning of the rifle, typically making it so the bolt stop will not be actuated sufficiently by the magazine follower such that the carrier will not be held back when the last round is fired out of a magazine. This is not a magazine problem, it is a problem with the add-on extended bolt release – take it off unless you are o.k. with function problems and alibis.
Adjustable Gas Blocks – Limited Application
Adjustable gas blocks have a limited application and are not good for all rifles, especially ones where the gas porting for the rifle is already correct and balanced for the rifle. Adjustable gas blocks are made for problem applications (i.e. mainly over ported AR-15’s) where there is too much gas causing an over cycling problem that needs to be addressed by throttling the gas flow back to make the firearm function best. All an adjustable gas block can do is restrict the gas flow into the gas system, it cannot add more gas flow than the gas system delivers (just like a valve in a pipe cannot make more flow through the pipe, it can only restrict it). In order for an adjustable gas block to be useful for our uppers we would have to deliberately over port the uppers just so we can use an adjustable gas block to throttle the excess gas back to where it should have been if we did our job right in the first place (and that makes no sense).
The other issue relates to reliability and simplicity. There is no adjustable AR-15 gas valve that can handle the highly pressurized hot gases full of abrasive particulate matter that won’t wear out and/or becoming unreliable over time. With rifles, it always seems like things fail at the worst time, so if you don’t need another moving part that wears out or can fail, why put it in there?
Does the 6mmAR Turbo 40 Imp. Cartridge Feed and Function In An AR-15?
Yes! The cartridge feeds and functions well in an AR-15. I am not sure why I am asked this so much but recently it seems to be the most asked question. It seems the question relates to whether it will feed out of a magazine with a 40 degree shoulder angle (vs the 30 degree angle of the 6mmAR). I believe when people are asking that question they are assuming that the shoulder of the cartridge somehow guides the case up into an AR-15 and that the steeper shoulder angle may present a problem. What I quickly found out after making the first prototype upper for the cartridge and shot it a while was that in an AR-15, the shoulder of the Turbo 40 (or the 6mmAR for that matter) normally does not contact with the feed ramps in that manner so as to guide the bullet into the chamber. What typically makes contact (if anything) is the corner edge at the junction of the shoulder and case wall of the case, which suggests one could make the shoulder angle even 45 or 50 degrees without issue (but I am not going there).
Copyright 2005 Robert Whitley. All rights reserved.