Anyone using an AR platform for F-Class?

[Jdne5b]

I kinda want to see what an AR-10 with a 30 inch barrel would look like.

I know of one that shot Fclass with a AR10, it was almost 28 inches. He was trying to plan a 30 inch build... but...

Built a bolt gun.

 

[Turbulent Turtle]

The gas system would have to be tuned for that 30 inch barrel or else the fired case would be ejecting while the bullet is past the gas hole but still has not reached the muzzle yet. If the shooter is very fast he could be loading the next round while the bullet is just exiting. That could create some issues down range.

A bolt gun is a better way to go, or leave out the gas system entirely and use a side-charger upper. Crap more expense and you lose the benefit of the automatic ejection of the fired case with all its heat.

 

[Mr. Ten-X]

Shot an 18" barreled AR15 in a 300yd event a couple of weeks back in F-TR using 77SIEMK's. That 1-3/8" X-Ring is a challenge, particularly if any fly passes gas as the booolit steaks by.

 

[chkunz]

The gas system would have to be tuned for that 30 inch barrel or else the fired case would be ejecting while the bullet is past the gas hole but still has not reached the muzzle yet. If the shooter is very fast he could be loading the next round while the bullet is just exiting. That could create some issues down range.

A bolt gun is a better way to go, or leave out the gas system entirely and use a side-charger upper. Crap more expense and you lose the benefit of the automatic ejection of the fired case with all its heat.

bayou shooter, You state "The gas system would have to be tuned for that 30 inch barrel or else the fired case would be ejecting while the bullet is past the gas hole but still has not reached the muzzle yet". Do you know this for fact or is this an assumption? I have heard this before and tried to do some calculations to see if this was realistic. We can have a fairly good assumption on the time the bullet is in the barrel once it passes the gas port but it seems like the time for the gas to get to the bolt is limited by sonic velocity of the gas. I had to make too many assumptions in my calculations so I gave up but someone who knows gas dynamics and how to deal with the equations might be able to do the calculations. I have not given this much more thought but am wondering if anyone else has tried to do a calculation. I know that White Oak Armament moves their gas block out two inches on their twenty six inch barrels and state "Our modified gas system delays the unlocking of the bolt. This reduces the stress on your brass, aids in longer case live, and also helps insure proper functioning with heavier bullets and slow burning powders." But they do not talk about where the bullet is in relation to other things going on with the gas system.

 

[chkunz]

Got the wrong guy.

Thanks, I did an edit to correct.

 

[Turbulent Turtle]

bayou shooter, You state "The gas system would have to be tuned for that 30 inch barrel or else the fired case would be ejecting while the bullet is past the gas hole but still has not reached the muzzle yet". Do you know this for fact or is this an assumption? I have heard this before and tried to do some calculations to see if this was realistic. We can have a fairly good assumption on the time the bullet is in the barrel once it passes the gas port but it seems like the time for the gas to get to the bolt is limited by sonic velocity of the gas. I had to make too many assumptions in my calculations so I gave up but someone who knows gas dynamics and how to deal with the equations might be able to do the calculations. I have not given this much more thought but am wondering if anyone else has tried to do a calculation. I know that White Oak Armament moves their gas block out two inches on their twenty six inch barrels and state "Our modified gas system delays the unlocking of the bolt. This reduces the stress on your brass, aids in longer case live, and also helps insure proper functioning with heavier bullets and slow burning powders." But they do not talk about where the bullet is in relation to other things going on with the gas system.

I do NOT know this as an empirical fact, in other words, I have never tried anything longer than a 26 inch barrel with a rifle length gas system to which I added a CWS with the heavy insert and a C/S action spring.

When I talked to the builders and competitors 5+ years ago, the position of the gas hole was discussed and we thought we would need to move it out one more probably two inches for a 28 inch and another 1 or 2 for a 30 inch. Certainly if you went with a 30 inch barrel you would definitely need to do something to the regular rifle length system, and that was my point here.

Of course, I facetiously exaggerated and talked about the case ejecting even before the bullet was out the bore, but I think it would at minimum start to unlock the bolt and that is done by rotating the bolt and the cartridge and if the cartridge is still under significant pressure at that time, it's not going to be good for the brass or the bolt, so retarding that event becomes a necessity.

This is further exacerbated when using heavier bullets, which is what you would want to do to get to 1000 yards.

I have been told by people whom I respect that the bullet would be safely out the bore before that happened, but I have seen super-slo-mo video of people shooting SR-25 and you can see the flames coming out of the chamber at the same time the muzzle flash appears. Either way, I think if the brass has a little more time to shrink back as the pressure goes to 1 atmosphere, there is less wear and tear on the brass or the rifle.

I noticed that when I was first shooting with my 26 inch. Adding the CWS and the C/S spring reduced the wear and tear on my brass.

 

[WindSurgeon]

Yes, you can use it. I used an AR for the first season to try out the sport. Short range only at 300 meters. I used my varmint rifle with bull barrel (8 twist), filled the A2 butt stock with lead shot to add weight and mounted a 24x scope. To make single loading easy, I purchased a single round follower from Sinclair. It is an accurate rifle for an AR. Will hold a .35 MOA group with precision hand loads (80 gr Berger VLD's) if conditions are perfect and I do my part. It was fine in club matches, but was frustrated I could never break the 192 mark for a 20 round string in FTR. I never shot it in competition at 600 yards, but I am sure I would be doubly frustrated. I, like many others who decided to go further in the sport and compete, went to a bolt action rifle purpose built. For what a quality AR goes for you can buy a savage F-Class rig for around $1200 new (800-900 used depending on the round count). I have seen guys shoot some really good scores with that gun especially in 6br. If you don't already have an AR to use, this is the rout I would recommend. Lots less frustration and the guns are fairly easily sold if you decide the sport is not for you.

I read some commentary on ejection timing in prior posts. If you go with an AR with longer barrel or hotter loads, you will want to add some mass to your carrier bolt to protect your brass from over expansion in the brass base. I added a Tubbs weight system that has seemed to solve the issue for me. It simply adds mass so the bolt disengages a few milliseconds after firing. Simple, but it seems to work and I was able to keep using my most accurate load which was a bit warmer than the norm for an AR. Here's the link to the thread: http://forum.accurateshooter.com/index.php?topic=3843906.0

 

[mac86951]

We do! Look at F-AR

http://www.chuckhawks.com/f-AR15_rifle.htm

http://www.ziarifleandpistolclub.com/f-class-centerfire-prone/

Ok, that said, the .308 would compete in F-TR following their regulations. It's possible to build a nice AR-10 to do so, but one of two outcomes will prevail. Either the match load for 1000y will be single loading by hand for heavier bullets, or you'll be loading within the 2.820" COL limits of the magazine. This is more than adequate to make a better shooter, but you technically might be at a slight disadvantage as compared to an F-TR Bolt rig. Personally, I'm planning on it, and I'm sticking to magazine length and a supply of 155 palma (not sure how it will feed) and 168-175 Conventionals to see how it performs.

I currently shoot two AR-15s in 600Y with .223 loaded to 2.260" The results are F-AR at 600y is typically 3-7 points below F-Open at our range. I'll quantify that by saying we only just scored our first F-Open perfect score recently, so you get an idea of our wind conditions at 600y.


Ok, enough said does that help?

-Mac

You can't shoot from a mag in f-class. All rounds are single round loaded. I can't imagine removing a mag at each shot, loading another round into it, then reinserting the mag in the rifle to shoot. I have seen newbies do this until I show them a sled.

Like Dennis stated, I did all the same mods to all my AR-15s to shoot HM scores at 600. But you will rarely beat a bolt rifle. "Slight disadvantage" is a huge understatement. My AR-10s will shoot master scores on a good day. By the time you modify an AR-10 to get to 1000 yards, you would save money by getting a bolt rifle. Glen Zediker has written some great books on getting the most out of an AR. Take the time to research this before you spend a ton of cash.

Scott

I'm always amazed at how so few people actually READ the links, or do their homework before posting.

Yes you can, and the reason why is well described in either link.

As far as I know there is NO rule that the rounds must be single loaded. It is most likely a benefit to single load, as you can seat to the lands that way; however, I haven't seen anything preventing the use of a magazine. Feel free to prove me wrong, since F-Class is an off-shoot to high-power competition I'd be interested in seeing that rule.

-Mac

 

[Turbulent Turtle]

Rule 10.1.6: Loading in Slow Fire—In all slow fire events, the rifle will be loaded with only one cartridge at a time. The cartridge shall be inserted in the magazine or chamber only when the rifle is pointed down range. Resting a loaded rifle on a shooting stool or on the foot, is prohibited. (See Rule 10.1.3).

Also, I suspect you've never shot in a real match because the final command before shooting starts with " With one round load, ready on the right..."

 

[WindSurgeon]

22. F-CLASS RIFLE RULES
NOTE: these rules are provided for the conduct of F-class competition
either separately or in conjunction with conventional NRA Long Range rifle
competition. Scores fired in these competitions using the F-class modified
targets will be used for classification.
In all cases where specific rules are not given here, the appropriate rules
for High Power Rifle competition shall be used

I believe F-Class is considered "Slow Fire" (or at least I shoot slowly over a full 20 minutes per match)

From the High Power Rules:

10.1.6 Loading in Slow Fire—In all slow fire events, the rifle will be
loaded with only one cartridge at a time. The cartridge shall be inserted in
the magazine or chamber only when the rifle is pointed down range.

 

[people]

Yup fclass single load. That local f AR class have to use a mag. That does look interesting form of comp.

That would give all those who made up knock off SAMR, and MK12 rifles up after coming back a good place to shoot.

 

[XTR]

As far as I know there is NO rule that the rounds must be single loaded. ....I'd be interested in seeing that rule.

-Mac

See the links in the posts above.

As far as I know, the only time in HP you feed from the magazine in an NRA sanctioned match (and you are required to) is during the rapid fire stage of Service Rifle. Even when shooting Service Rifle you are required to single load all rounds during any stage other than rapid fire.

The F-AR matches mentioned here are not NRA sanctioned events

 

[effendude]

[/quote]

I'm always amazed at how so few people actually READ the links, or do their homework before posting.

Yes you can, and the reason why is well described in either link.

As far as I know there is NO rule that the rounds must be single loaded. It is most likely a benefit to single load, as you can seat to the lands that way; however, I haven't seen anything preventing the use of a magazine. Feel free to prove me wrong, since F-Class is an off-shoot to high-power competition I'd be interested in seeing that rule.

-Mac
[/quote]
I too am amazed at how some people who don't know the NRA rules, have not read the NRA rule book, have not shot in a NRA sanctioned match or ran a NRA sanctioned match will assume people who have are wrong. All of this based on their limited experience with club matches or gravel pit ego shoots didn't follow or at least disregarded the NRA rules.
Scott

 

[Road_Clam]

Do you ever see any AR platforms at F-class matches? I have a friend who thinks he wants to try F-class, but wants to build an AR in .308 to do it. Could it be done?

I have not yet embarked on F class competition, but I plan on it. However I do frequently shoot both a 24" barreled AR-15 Varmint, and a traditional R700 .308 Varmint bolt. While I do get amazing accuracy from my AR it's not really up to serious accuracy as compared to my bolt. You have to deal with a serious bullet jump with the AR type chamber and gas system. Even with a precise load shooting 69 gr SMK's the best I have shot thus far is about 3 moa @ 600 yards, which is great considering it's a basically box stock Bushmaster AR with the addition of accurizer inserts.

 

[chkunz]

Do you ever see any AR platforms at F-class matches? I have a friend who thinks he wants to try F-class, but wants to build an AR in .308 to do it. Could it be done?

I have not yet embarked on F class competition, but I plan on it. However I do frequently shoot both a 24" barreled AR-15 Varmint, and a traditional R700 .308 Varmint bolt. While I do get amazing accuracy from my AR it's not really up to serious accuracy as compared to my bolt. You have to deal with a serious bullet jump with the AR type chamber and gas system. Even with a precise load shooting 69 gr SMK's the best I have shot thus far is about 3 moa @ 600 yards, which is great considering it's a basically box stock Bushmaster AR with the addition of accurizer inserts.

The 69 SMK is not the bullet for your AR at 600 yards. You will get much better results with the 80 SMK or even the 77 SMK.

 

[mac86951]

Rule 10.1.6: Loading in Slow Fire—In all slow fire events, the rifle will be loaded with only one cartridge at a time. The cartridge shall be inserted in the magazine or chamber only when the rifle is pointed down range. Resting a loaded rifle on a shooting stool or on the foot, is prohibited. (See Rule 10.1.3).

Also, I suspect you've never shot in a real match because the final command before shooting starts with " With one round load, ready on the right..."

Thank you Bayou! I stand corrected on single fire, but I see plain and clear that there is allowance for a Magazine!

-Mac

 

[mac86951]

Do you ever see any AR platforms at F-class matches? I have a friend who thinks he wants to try F-class, but wants to build an AR in .308 to do it. Could it be done?

I have not yet embarked on F class competition, but I plan on it. However I do frequently shoot both a 24" barreled AR-15 Varmint, and a traditional R700 .308 Varmint bolt. While I do get amazing accuracy from my AR it's not really up to serious accuracy as compared to my bolt. You have to deal with a serious bullet jump with the AR type chamber and gas system. Even with a precise load shooting 69 gr SMK's the best I have shot thus far is about 3 moa @ 600 yards, which is great considering it's a basically box stock Bushmaster AR with the addition of accurizer inserts.

The 69 SMK is not the bullet for your AR at 600 yards. You will get much better results with the 80 SMK or even the 77 SMK.

We've found the 77 Berger OTM to be the default bullet to use, but if you have the barrel length, the 70gr Berger VLD is doing well too, if you need to stay within 2.260 COL. As soon as you load longer, the 80gr and up are the go-to bullets.

It depends on where the accuracy node is with velocity, that and 1 mph error on your wind call will shift poi ~3"

 

[Turbulent Turtle]

Rule 10.1.6: Loading in Slow Fire—In all slow fire events, the rifle will be loaded with only one cartridge at a time. The cartridge shall be inserted in the magazine or chamber only when the rifle is pointed down range. Resting a loaded rifle on a shooting stool or on the foot, is prohibited. (See Rule 10.1.3).

Also, I suspect you've never shot in a real match because the final command before shooting starts with " With one round load, ready on the right..."

Thank you Bayou! I stand corrected on single fire, but I see plain and clear that there is allowance for a Magazine!

-Mac

If you want to load from a magazine, that's certainly your option, but it will be one round at a time meaning you need 20 magazines with one round loaded or putting a round in the same magazine for every shot, which is just about as stupid as one can get. Enter the Bobsled or the magazine cutoff things which never worked 100% for me.

I will point out that your ersatz format is a disservice to anyone following your made-up rules. Your shooters can never get NRA classification or shoot in any other venue and I thinks that's sad. As a soon-to-be-erstwhile match director, I put in extra effort so that our shooters met all the specifications and could get NRA classification legitimately. You would be surprised at how many came back to me to express their appreciation for us following the rules as they got their cards from the NRA. That was a big deal for me for the last several years.

 

[people]

If you want to load from a magazine, that's certainly your option, but it will be one round at a time meaning you need 20 magazines with one round loaded or putting a round in the same magazine for every shot, which is just about as stupid as one can get. Enter the Bobsled or the magazine cutoff things which never worked 100% for me.

I will point out that your ersatz format is a disservice to anyone following your made-up rules. Your shooters can never get NRA classification or shoot in any other venue and I thinks that's sad. As a soon-to-be-erstwhile match director, I put in extra effort so that our shooters met all the specifications and could get NRA classification legitimately. You would be surprised at how many came back to me to express their appreciation for us following the rules as they got their cards from the NRA. That was a big deal for me for the last several years.

Why would you want a NRA classification?

 

[XTR]

If you want to load from a magazine, that's certainly your option, but it will be one round at a time meaning you need 20 magazines with one round loaded or putting a round in the same magazine for every shot, which is just about as stupid as one can get. Enter the Bobsled or the magazine cutoff things which never worked 100% for me.

I will point out that your ersatz format is a disservice to anyone following your made-up rules. Your shooters can never get NRA classification or shoot in any other venue and I thinks that's sad. As a soon-to-be-erstwhile match director, I put in extra effort so that our shooters met all the specifications and could get NRA classification legitimately. You would be surprised at how many came back to me to express their appreciation for us following the rules as they got their cards from the NRA. That was a big deal for me for the last several years.

Why would you want a NRA classification?

Why would you not?

If you plan to compete in larger NRA sanctioned events there are awards for winning your classification. It lest you compare your performance to people who have developed similar skills, and it gives a way of tracking your improvement.

Off the top of my head I think over the yrs I've won my classification (SS and EX) at at least two regionals.

At some events with enough shooters people are squadded (at least initially) by classification so you are shooting with the people you are competing against. Reality is that someone carrying a MK card isn't going to out shoot an EX very often. If you have no classification you shoot as a "Master (unclassified)"

It's also a bit of recognition for accomplishment. In F-TR getting to Expert shooting long range is a goal and it really does show that you have started to understand and can play the game with skill.

Personally, in Long Range, I worked from Marksman to Sharpshooter to Expert and have flirted with Master on a couple of occasions but have never strung together the scores to get there. (it takes 120 shots for record to reclassify). In F-TR there are (or at least were before PHX) several members of the US team that carried EX classifications. Getting a MA classification in F-TR is hard, and getting my Master classification shooting F-TR is a goal that I intend to reach.


Prior to this yr I never shot much mid range and when I did I usually used the matches as laod work for long range, but I've finally played mid range enough this past yr to get my HM card. It's nice to get that in the mail. I personally think is too easy to get at mid range shooting F-class, but it is what is is for now.

As for my personal opinions of the classification system, I personally think F-Class mid range HM should be at 99%, not the 98% or 98.5% or whatever it is today, and I think that Long Range HM is too difficult to achieve shooting F-TR. Not many people, even with great skill, will ever see conditions that will let them post 6 matches averaging 196 or better in a row with a 308 at 1000 yards. I think the only two people who have accomplished it on the 1MOA target with an F-TR Rifle are Danny Biggs, and if I read the scores correctly from PHX this yr, Jim Crofts. It should be hard to achieve, but there should be more than two.