difference between custom and production barrels

Frequently Asked Questions

Scope mounts & accuracy
DO NOT mount 1 scope mount on the receiver and 1 on the handguard accuracy will be terrible because of flex in the handguard. Use the proper cantilever scope mount. Squeeze the trigger and follow through(hold the trigger back, do not allow it to reset until the bullet contacts the target)to get the best accuracy. Use a good sand bag or rest on a stable platform not the hood or tailgate of the truck.
What is the difference between our 6.8 x 43 and the SPCII?
Both chambers will allow the use of any 6.8 ammo including SSA Tac loads and Wilson Combats SPCII loads. The ARP designed chamber uses a bullet diameter leade which aligns the bullet in the bore better than the SPC II. Our chamber was designed to fix a cone angle error in the original SPCII chamber in 2007. Both chambers use the same brass and reloading dies. The new SPCII(as of 6/2010) has .114" freebore where the 6.8x43 has a .095" long freebore so it doesn't have as much jump to the lands as the new SPCII and can be more accurate.
What caliber for what use?
5.56 for training, varmints, target, 3 gun and home defense. The cost and availability of parts makes it the easist and smartest choice. 6.8 for hunting deer and hogs but can be used as a very effective home defense rifle. 264 LBC if longer range target shooting is #1 on the agenda with hunting deer and hogs as a second consideration as well as HD. 6x41 ARP if longer range varmint hunting is #1 on the agenda with deer and hog hunting being second, could also be used for HD. 30HRT if you just have to use a 30 cal. It will shoot subsonic just like the others but offers apx 300fps more than the little 30 cals on the top end velocity. Good for deer and hog hunting and HD. For High Power the 5.56 makes the most sense and keeps you in the service rifle class. If moving to open class IMO you need every advantage possible so the 6BRX would be a great long range competition rifle. Longer range hunting- the 6.5BR or 6.5BRX has higher BC bullets and better velocities to extend the range of terminal performance.
What do you recommend for a piston system?
None, we will no longer install ANY piston system on our rifles. If you use our bolts in a rifle with a piston system and the bolt breaks at the cam pin hole it will not be covered under warranty. IMO piston systems cause more problems than they fix.
Why did we choose to nitro-carburize our barrels instead of chrome lining them?
Nitro-Carburizing, Melonite, QPQ is a heat treat process for barrels that harden the barrels to apx 70 Rockwell so they last longer, are more corrosion resistant inside and out and it also decreases friction in the barrel which can increase velocity. Chrome lined barrels can decrease accuracy as it is a built up layer inside the barrel. Nitro-carburizing changes the structure of the metal without building a layer in the bore increasing performance but,not decreasing accuracy. The S-Carb treatment we use on use SS barrels is a slight modification to the QPQ process, our SS test samples tested harder than our CM samples, the SS barrels could last longer assuming hardness increases durability.
Why did we choose an 11.25 twist?
In our four years of testing, we've found that 6.8 bullets don't need the 10 twist to stabilize the bullets used in the 6.8. Having already requested competition LD bullets from GS Customs (99gr SP) designed specifically for the 6.8. We believed an 11.25 twist would work best to stabilize these longer LD bullets.
Where does the 5R rifling come into play?
Again our four years of testing has shown us that the land to groove ratio can cause significant variations in peak pressure created in the barrel as well as velocity obtained. As a result, we changed the land to groove ratio in the 11.25 twist/5R buttons to reduce peak pressure, which allows us to use stiffer charges in our hand loads and obtain more velocity without increasing pressure.
How does the ARP chamber combat the forcing cone angle in the SPCII?
Inside the chamber at the end of the case mouth, the angle slopes from the outside of the case neck to the bullet leade. As the bullet enters the chamber, it scrapes over the top of that angle. The 45 degree angle in the ARP chamber is less likely to scrape copper off the bullet jacket and damage the projectile in the process. Some SPC II chambers have an 80 degree angle, which is more likely to scrape copper from the bullets and form a copper ring which can build excess pressure.
What makes our SuperBolt so super?
We have taken the current AR15 bolt to the next level by completely redesigning the lugs and cam pin area as well as using a stronger 9310 alloy to make this the most durable bolt on the market. The lugs and cam pin area are the most common breakage areas on standard AR bolts. To combat these breakage prone areas, we have re-engineered the cam pin area to be 17% greater on each side with the actual hole slightly smaller to remove any play to reduce potential breaking in this area. The lug attachment to the web of the bolt has been increased by 40% with the addition of a larger radius at the root of the lug. The bolts are machined from 9310 alloy steel which is significantly stronger than any commercial bolt material (8620 cold rolled) combining the alloy and design change makes these bolts the strongest on the market.
Can we use your products with other mil spec products
YES, we've designed all of our products to work with standard mil spec parts. Adams arms piston carriers do not work with our bolts as they have made the bore of the carrier smaller than in the standard mil spec carrier that we used in designing our bolts.
"match" and "ultra match" barrels , what are they?
The term "match" and "ultra match" are used too loosely, most companies advertising "match" barrels for $200 are just using the term as a sales gimmick. True "match" barrels are lapped to start with so a quick inspection with a bore scope will tell you if it could be a match barrel or not. If it looks like rumble strips on the side of the highway then you know it's not a match grade barrel. Match barrels are held to tighter tolerances than production barrels and are lapped and air gauged. Match grade barrels will not make bad ammo shoot well, they allow good ammo to shoot to it's capability. Our production grade barrels are the same brand that Wilson Combat uses, our custom barrels are lapped and a better quality.
How does the 11-12 twist get more velocity?
Recently a writer said he tried a 11 twist barrel and saw minimal increase in velocity compared to a 10 twist. The velocity in most cases does not just magically appear. The 11 and 12 twist barrels with high performance rifling specs lower the peak pressure in the chamber and barrel, that allows handloaders to add more powder to get back up to max peak pressure levels and that increases velocity, sometimes as much as 200fps over factory ammo. If all barrels had better specs factories could load higher performance ammo but due to the 9.5 twist barrels floating around they would be liable if the stronger ammo destroyed one of those rifles.
What are the coatings?
The TiAlN(Titanium Aluminum Nitride) is apx 90 Rockwell, the Nitro(Melonite) carrier is apx 70 Rockwell, NP3(Nickle Boron) is 48 to 51 Rockwell and chrome is 66 - 70 Rockwell but most chrome carriers on the market are decorative chrome not hard chrome, The anodized receivers are 70 Rockwell and very abrasive...The TiAlN goes on in a much thinner layer than chrome or NP3, the Melonite is a heat treat not a coating...The military stopped using chrome bolts during the Viet Nam war due to rust growth underneath the chrome finish...The Titanium Nitride keeps the lubricity for longer periods. The NP3 is very soft but teflon impregnated nickel so it is very slick as well. Any of these coatings are better than a mil spec phosphate carrier, they should all be easier to clean, common sense would say the harder the surface the longer the coating will last.
Do your rifles shoot Remington or Hornady 6.8 SPC ammo? How is the performance?
Yes they will shoot any factory ammo and the design of the throat and barrels will allow the use of more powerful handloads than most standard 6.8 SPCs. The chamber size is the same and uses 6.8 reloading dies just like all other 6.8s. We recommend the Hornady 110gr HPBT, the Vmax has not proven accurate in our tests. We do not recommend the use of large primer brass or ammo loaded with silver primers other than CCI450s or Wolf Magnums, CCI 41s are mil spec primers, brass colored, determined by the mil to be the best primers for use in AR15s. If you use large primers or thin cup small primers and the gases burn through the primer(pierce) or leak around the primer and erode the bolt face it is not covered under warranty.
6.5 VS 6.8 in trajectory comparison
6.5 Grendel using Alexander's own max loads published on the Grendel forum in a 16" barrel- zeroed at 200yds drops at 300yds. due to energy being less than 1000ft lbs 300 yds is about max for taking deer or hogs. the same temp, pressure line of sight and program used to figure all drops in both calibers. 100 Nosler-2600fps--drop 9.4/801 ft lbs 107 SMK-2545fps-----drop9.5/878ft lbs 123 SMK-2472fps----drop 9.4/1083ft lbs 120TSX-2472fps----drop9.8/984ft lbs 6.8 SPC SSA factory ammo 16" barrel 100 Nosler-2700fps--drop9.0/809ft lbs 110 Nosler-2630fps--drop9.0/939ft lbs 6.8 handloads max 100 Nosler 2950fps---drop 7.4/993ftlbs 110 Nosler 2750fps--drop8.2/1040ftlbs As you can see not only does the 6.8 not loose anything to the Grendel out to 300 it performs better with some bullets. The higher velocity of the 6.8 will hold it's own out to 500yds against the Grendel.
What payments do you accept? when will you charge my card?
We accept VISA, Master Card or Discover. When placing orders through the site, your card will be authorized immediately and for those who call and place their order over the phone, cards will be charged the day we start the build, within 7 days of the order being shipped. When you give the wrong billing address, whether through the site or ordering by phone, the transaction will decline due to the address mismatch but the amount will be authorized through your bank account. This amount will show as a pending charge but we cannot "settle" the charge as we did not receive an approval code. The bank will release those funds within 72 hours. When we run the transaction with the correct billing address, the amount is authorized and we can settle the charge with the approval code. We do not accept American Express or personal checks.
Ammo is sticking in my chamber, what is wrong?
If the ammo is handloaded it could be that the case was not sized down enough, it should be .003-.004 below the chamber size in every dimension. If it is factory ammo measure the case with calipers or a mic. and compare the dimensions to SAAMI spec, if the ammo is larger than SAAMI spec that is the problem. On the 6.8 the base should be apx .418 the neck .306 or under. Check the neck carefully as some factory ammo is known for larger than spec neck sizes.
can I order an option not shown on the options list?
We have carefully chosen each option available on our website due to quality, price and availability. For those of you who request items not listed as options or parts we generally carry, there will be a surcharge based on single item shipping and possible lack of dealer pricing.
will you build an upper using my parts?
No
custom 1 off barrel?
Sorry, we just do not have the time the make custom 1 off barrels or change the contour on the barrels we sell. We contract at a minimum 100 barrels to a shop that specializes in AR15 barrels.
will you work on my upper or rifle?
No, we are not set up as a smithing shop. We do not flute customer owned barrels. ADCO's primary business is smithing try them.
do you have reloading data? which bullets work?
Reloading data can be found at most powder manufacturers web sites. If you are an experienced reloader you can get much more velocity with careful loading. The Speer 90gr TNT, Sierra Pro-hunter and Hornady 110gr HPBT seem to be accurate in every barrel I have shot or made. To get the best accuracy requires hand loading to an OAL of 2.295- 2.3" Pri mags allow that length. We recommend the use of CCI 41 primers, CCI 450 or Wolf Magnum primers, any erosion to the bolt face by the use of other primers will not be covered under warranty.
Recommended bullets
Deer-110gr Sierra Prohunter, accurate, inexpensive, opens better on thin skinned deer than the TSX does. Hogs- Barnes 85gr TSX, 110gr TSX, penetrate tough shoulders, retain weight better than any other bullet made, accurate, can be pushed to 3050fps. Varmints- Speer 90gr TNT, very accurate with 29.2 gr of RE7 loaded to 2.295" also a great target bullet. longer range-Hornady 120gr SST Home defense-Hornady 110gr HPBT For all out accuracy Hornady's brass seem to be more consistant in weight and neck thickness.
What is the difference between a precision hand load and a reloaded cartridge?
to get sub MOA groups, the loads have to be tailored to match the rifle and you must be very meticulous with the loading. "Precision Shooting's" Reloading Guide is a must read for this type of loading. Link at the bottom of this section. If you want to test the accuracy of your 5.56 barrel try 24gr of RE15 with a 69gr SMK set to an OAL of 2.285" that is more accurate than ANY factory load in every Wylde chambered barrel I have ever shot.
Can I use 5.56 mags in my XXX rifle?
No, the 7.62x39 requires 7.62x39 mags, the 5.45x39 use 5.45 mags, the 6.8 needs 6.8 mags. In general most cartridges require a special mag except the 6mmx45 or other cartridges based on the .223/5.56
Should I do anything different when ordering my upper if I plan to use a heavy spring and buffer
Please let us know when you order if you plan to use a heavy duty spring and buffer assembly so that we can port the barrel accordingly. When a customer puts a standard upper on THEIR lower with a hd spring and buffer assembly, shortstroking may result. This is caused by the hd spring and buffer, NOT ARP's upper configuration so it is important to let us know what buffer and spring you plan to use.
Can I use steel case ammo in ARP rifles?
Yes, the mid gas system allows more time for the cases to shrink back down aiding extraction. The Nitro treatment makes the chambers 70 Rockwell and very slick also aiding extraction, Our Nitro carburized barrels were made to handle steel cased ammo.
Why did we remove the railed aluminum gas block from standard builds?
Due to the varied expansion rates of aluminum, we chose to offer instead, the YHM steel railed gas block as a $20 upgrade.
What do I need to provide to qualify for an active Mil/LE discount?
Scan and email a copy of your active id to tech@ar15performance.com OR, send a photocopy of id with your money if that is how you choose to pay. Avail only on selected uppers and rifles, no barrels or parts.
What do I recommend for a 3 gun rifle?
Obviously if you are a world class shooter you are not reading the FAQs here but if you are just getting in to it for recreational purposes then if the shots are 0- 300yds a lightweight 16-18" .223 with a midlength gas system and a light carrier and buffer tuned to work together. The twist would depend on the bullets you plan to use and any other uses you may have planned for the rifle. I like a EO Tech sight they seem to be a little faster to locate the targets and I usually have no problems connecting on targets out to 300yds. If you happen to shoot longer ranges you may want to consider a ACOG or a low power scope with a wide FOV. If you shoot smaller local shoots and they do not use flashers and the RO relies on sight and hearing the ding then a 6.8 could clarify those judgement calls when the steels are out at 200yds or more.

Precision Shootings reloading guide