Pegasus

BTW, on the subject of accurizing your AR; step no 1 is NOT to cut your barrel down to 13 inches. The basic rules of accuracy for any AR is to float a good barrel and shoot good ammo.

StainTrain, wind noise in a microphone is meaningless; you get that just breathing on it. Look at the ground, look around the target; nothing, not even any hint of mirage either. There was no wind. I am glad we now all agree that barrel length is important, especially when you go to longer distances and have higher accuracy requirements. I know what you mean about people being resistant to change; I fall in that category a lot as I get older; 60 in a few months. The wind tomorrow will be coming from the right at 4-8 gusting to 20MPH. May be some rain also, lots of mirage. Should be fun, good practice for the Nationals next month.

98Z5V, I did a search for your experiences with 300Blk loadings and brass quality and did not find anything right away. Would you be so kind as to either point me to the discussion(s) or recap for me your findings here, please?

Thanks for the nice welcome blue109. BTW, that's "elitist" and you need to learn to capitalize the first word of every sentence.

Yes, that is correct. Brass quality will factor into this equation. I start with virgin Lapua brass in my match rifles, but in my AT-10(T) I use Winchester brass. The ejection is violent especially compared to my bolt guns, so it's not worth spending the cash on Lapua. However, Winchester is good brass, it just needs more prep than Lapua at the first loading and after that it's pretty much the same. It is important to adjust your sizing die properly to get good brass life and you don't want head separation in a .308AR.

StainTrain, there is no wind to be seen anywhere on the video. If there is any, I would be funneled front or back, not side to side and I think you know that front and rear winds have little to no effect on the bullets. On the other hand the shooter was not holding the waterline worth a sh*t. At 800 yards, I can pretty much clean an F-class LR1-FC target; he was all over the place on that silhouette. It's silly to compare a 9inch .300 Blackout with a .308 Match rifle or sniper rifle at that range. The guy is trying to sell the rifle. It can do everything under perfect conditions. Is that really something you would foist on our military sniper teams? I wouldn't. Barrel length is important at long range, I don't really care who thinks it doesn't. Just got to a Palma match and look at the rifles. Go to Camp Perry and look at the rifles for the LR matches.

StainTrain, you posted a great message and I appreciate the fact you kept it on topic, well for the most part. I've been shooting competitively for over 30 years and for the last 8 years or so, it has been all F-class, F-TR to be exact, most of it at 1000 yards. I shot at least one NRA sanctioned competition every month at 1000 yards and have been doing this for all that time. As a matter of fact I will be shooting one tomorrow morning. My log books show more than 15,000 rounds fired competitively at 1000 yards; I think that allows me to navigate under the impression that I know a little bit about it. I hold ratings of NRA High Master at Mid-range and NRA Master at Long range, all in F-TR, with my trusty rusty .308 Winchester. The article we are discussing is what you call, an opinion. I specifically pulled a sentence from it to explain why it was wrong. At long range, conditions rule and if you can read and allow for them, you're toast. I have stated many times here that I am not a sniper, I know nothing of sniper craft, nor will I ever be a sniper. I am a competitive shooter. I never make any pretense that I would be able to do whatever it is that snipers do. Now, there is a reason why the military uses .300 Win Mags, .338 Lapua and 50BMG for long range snipping; can you guess what that would be? I was not aware that this forum was geared for snipers and snipers wannabees. I thought I could discuss ways and methodologies for accurizing 308ARs. When I look at my AR-10(T), I totally understand that it will never be able to keep up with my F-TR match rifles, at any distance. But I use my knowledge of what can be accomplished with a .308 Winchester to try to maximize the accuracy of my AR-10(T). And I am happy to share that knowledge with other owners of .308ARs. Finally, you seem like a reasonable person, certainly a lot more reasonable to some others here so I will just say this: I am a member of many forums and this one is about as nasty and aggressive as I have ever encountered. You may think this is a friendly welcoming crowd, it's not. But thanks for the welcome, I do appreciate it.

Thank you 392heminut, Gibbs, washguy and microgunner. Dane Armory, I may be a newbie to this site, but that doesn't mean I don't know what I'm talking about. I would say there are some high post count members who have attitudes. Notice the spelling of that word. It's not arrogance if you can do it. And I think you mean that I may not "fare" well, notice the spelling of that word also. And thank you for the welcome.

Robocop1051. A neat video and one that I have seen before, but it's always fun to see it again. I watched the whole thing and it was great. I have two observations. 1- When he was shooting at the steel silhouette, there was not a breath of wind. He's in some type of valley or pit and the conditions are eliminated. All he has to contend with is elevation. Trust me when I say that conditions make a huge difference at long range. 2- About your last line: "... if you want to see how a Sniper... A truly accomplished sniper... views accuracy." I've said it before, I am not a sniper, never was and never will be. I am a competition shooter, an F-TR LR competition shooter. F-Class is not sniping. And just so you know I have competed alongside snipers from various branches and alphabet agencies over the years, some were retired and others were active duty on leave. We always extend a very warm welcome to them, as we have a special affinity with them. Remembering that this thread is about barrel length and its effect on accuracy; a 24 inch barrel shooting M118LR is hard pressed going against a 32 inch barrel spitting out substantially higher BC bullets at 1000 yards, in conditions. Sniping is not F-Class. And thanks for the nice welcome.

Matt.cross, I love your humor and I totally agree with you; a 32 inch AR would be more like a crew served weapon than something to take hunting or anything further than from the back of the SUV to the firing line. And thank you for the warm welcome. I had seen the video before and it is pretty awesome, Jerry is quite the shooter. Did you catch him on Stan Lee's Superhuman show last week on the History Channel? Amazing stuff.

If you are talking about the exact same style and composition for the bullets, then you are correct. But that's a limited view of what is available and the question was weights and twists; it didn't say anything one specific style. Survivalshop even mentioned there are many bullet types and weights. For example, if you compare a Sierra 175MK, arguably one of the best mag-length bullets, with a length of 1.240 inches to a Berger 155 Hybrid, which has a length of 1.280 inches, you can see that the heavier bullet is actually shorter than the lighter bullet and they are both BTHP, jacketed lead core bullets. You can be quite sure that even though the 155 only weighs 5 grains more than a 150gr FMJ-BT, it will require a faster twist to stabilize. And please, do not tell me what to do.

Thank you, planeflyer21. Nice OV-10A you got there. I will be in AZ next month for the FCNC.

I'm in the Houston area. Thanks for the kind words.

A small base die does not make a case shorter, unless you have adjusted it wrong. What a small base die does is to shrink the OD at the base of the case, hence the name "small base". You adjust the shoulder bump in a die by screwing it in or unscrewing it and using a comparator to measure. If you only measure the overall case length in your sizing operation, you're doing it all wrong. The .308 Winchester headspaces on the datum line which is a point midway in the shoulder where the outside diameter of the cartridge measures .400 inch, if memory serves. At that point the distance to the base of the case should be right around 1.634 inch give or take, and again that's from memory. So, what you want to do is take a fired case, and measure its length from the base to the datum line and then set your die (small base or regular F/L) to push back that shoulder a couple thousands, IF (and that's an important IF) you will be shooting it in the same rifle. If you want to shoot it in a variety of rifles, then push back the datum line to SAAMI specs. Now, if you cannot screw in the die any further and still have the press operate, you may want to look at other shellholders as the one you are using may be too thick or dirty. You can then trim the case to 2.005 or shorter, but only after it has been sized properly. Doing it any other way is pointless and will cause various unpleasantness. So, either SAAMI or .002 under your chamber. Also, when you resize, count to 5 when the case is fully in the die to give it time to resize, then lower the ram. People who just speed through the sizing operation are not doing it right. Small base dies do not work the brass more, if you use them all the time. This will only occur if the base has expanded due to sloppy chamber and or heavy loads. These cases are difficult to resize properly and will not chamber easily if some chambers even if all the other dimensions are right.

Thanks for the nice welcome folks. It should be fun around here. ^-^ I'll get the details of that rifle posted over the weekend. It's still a work in progress as I am the eternal tinkerer and what better platform to tinker with than the AR?

I realize this will sound even more crass than my second post (my first one was in the introduction forum,) but I have more experience pushing .308 caliber bullets from a .308 Winchester than probably anyone here. I have been doing this for 30+ years, starting with Fullbore, Palma and more recently F-TR at the local, regional, state, national and world level. I shoot competition every month, year in and year out and then add to that regional, state, and national competitions and the Worlds every 4 years. I live and breathe .308 LR. What people seem to forget is that competitors (like snipers,) have to shoot in whatever the conditions are. Can you get a nice 3-shot group at 1000 yards with your tactical rifle? Absolutely, when the conditions are right. Now, can you go out on command and push 15 to 20 rounds on the 1000 yard target and get the same group, every time, regardless of conditions? While I can do that with my long barreled F-TR rifle, I don't even want to go there with my 20 inch AR-10, even if I used the same ammo as in my F-TR rifle. That extra 250-300FPS makes a huge difference and that's what my point was. I don't really care about the replies I got, they just come from people who have never shot at 1000 yards, because anyone who has ever done that would not be disputing what I said. Given the same level of marksmanship, a rifleman with a long barreled rifle will perform better than a rifleman with a short barreled rifle at long ranges. I stated that article was a joke and it still is.

If you limit yourself to anything that you can load to mag length in a .308AR, a 1:12 twist will be just fine and a 1:11.25 or 1:11 (my personal favorite for long range) will be even better. My Ar-10(T) has a 1:10 twist so I'm not worried about loading anything in there. However, that said, the beauty of the AR platform is that you can single load if you want. If you ever compete in XTC or NRA HP, you have to single load at anything greater than 300 yards. The AR platform is amazingly flexible and it will allow you to single load with no problems. I have a Bobsled for one of my AR-15s (NM) and I also have a Bobsled for my AR-10(T). If ever I get the urge to try a really long bullet like some of the VLDs that I use for F-TR in my AR-10, I can. That's flexibility. Did I mention that I love the AR platform? Now, in answer to the question which twists work best with which bullets, my thinking is that the question is reverse of what it should be. What you want to know is which bullets lengths or weights will not work for specific twists. Then you can experiment with what remains. So, a 1:10 will not like bullets that are heavier than 230 grains. (Notice that I don't use length here because nobody sells bullets by lengths. I invite you to check out JBM's database of bullet lengths. For a 1:11 or 1:11.25 twist anything much past 200gr will be iffy, but do remember that plastic tips don't count. For a 1:12 twist, anything heavier than a 175/180gr gets iffy. You can visit the web site of various bulletmakers to see what their recommendations are. I usually subtract one more inch from their recommended twists. So if a site suggest a 1:12 twist for their bullet, I use 1:11. JBM has a stability calculator, and I would recommend that the minimum stability you want to have is 1.5 for your bullet/twist/velocity combo.

I will also state that I have no delusions of being a sniper. F-class is NOT sniping; it's F-class. At 1000 yards, we have to shoot 15 or 20 consecutive rounds at a target where the X-ring is 5 inches in diameter and the 10-ring is 10 inches, and so on. Our target does not move, does not fire back, and we know the exact distance to it and that does not change. On the other hand, we do not have a spotter to feed us corrections and every one of our shots counts and is scored. As you can see, it's totally different. Since I am a civilian and old(ish), I have no expectations or desire of ever going out to snipe at people at 1000 yards. I compete in F-TR and I also enjoy shooting my AR-10(T) at paper targets. Since it's all the same caliber, there is some synergy going on here and what I have learned in F-TR helps me set up my AR-10(T), albeit for much shorter ranges. If your goal is to emulate snipers, I fear there is little I can contribute. But if you want to talk .308 out of an AR, well, that's different.

Interesting. The OP posted an article that stated barrel length made no difference in accuracy and totally dismissed the concept of conditions at long range with the specific text I quoted in my original post. I thought this was a .308 AR forum, where we can discuss .308 ballistics. I shoot F-TR, which is all about .308 Win and as it happens, my AR-10(T) also shoots .308Win. I have some experience shooting the .208 Win at long ranges and I am here to tell you that shooting that cartridge from an AR-platform is not going to enhance the ballistics of the bullet over what comes out of my match F-TR rifles. I know what can be done with a .308 Win at long ranges and I know what it takes to get that level of performance out of that cartridge. I do not expect anywhere near that level of accuracy out of my AR-10 and I have no intention of shooting it at these ranges but it's fun to read what some people claim to be able to do. So, I just thought I would share some of my experience with .308 Win ballistics with people who shoot the same cartridge and maybe help set their expectations to a proper level. I do look forward to seeing pictures of your 32 inch barreled 308AR. What barrelmaker do you plan to use for that?

I read the article in the OP and I must say that I had tears in my eyes halfway through it; it was that funny! My favorite line was this one: "There is a downside to longer ranges and reduced velocities, that being increase susceptibility to wind as range increases. Increased drift is not the end of the world, though, and if measured properly, can be overcome with ease." Truly words spoke be someone who has never shot beyond 4-500 yards in any type of competition. There is a reason why F-class shooters and Palma shooters have long barrels on their rifle and I can assure you that if short barrels were just as accurate at long range, I would swap length for a heavier contour in a heartbeat. I see people coming to the 1000 yard line all the time with their 20 and 24 inch "tactical" rifles and then wonder why their bullets are all over the target or even off it in stronger winds. I have been using a 32 inch barrel for 1000 yard competition for years and every last bit of velocity you can extract and still be in an accuracy node is worth it. "Measured properly." How in the heck can you measure the wind 750 downrange properly? I difference of a couple of MPH in a full value wind will push the bullet out of the 10 ring and maybe into the 8-ring. The slower the bullet the longer it gets buffeted by the conditions. Also, you need to be more than just supersonic to be precise, you want to be outside the transonic range and that's from Mach .095 to about Mach 1.25. And don't forget that while the speed of sound decreases only with temperature, the air resistance increases even faster the colder it gets, so your bullets will go transonic faster when it's cold.

Just so you know. 1:11.25 is a fine twist for the .308 Win pushing bullets as heavy as 180 or 190 grs. I've pushed 200SMKs to 1000 yards in one of my F-TR rifles which has that specific twist. The weight of the bullet is not the main determining factor in selecting the twist rate; bullet length is. Most .308 rifles are 1:12 twist but as mentioned before, there are 1:11.25, 1:11 and 1:10 twists in many 308ARs. If your twist is too slow, the bullet will be unstable when it leaves the bore and will start tumbling and you can see this a oblong holes or keyholes on the target, if it even gets there. If your twist is too fast, the bullet could spontaneously disintegrate 50-70 yards downrange, but while I have seen lots of 6mm bullets undergo the sudden transformation from bullet to white puff cylinder downrange, I have never seen or heard of a regular .30 caliber bullet doing that. It is generally accepted that spinning a bullet fast can help accuracy, but there are many caveats to that statement. Let's just say that as long as you use nothing heavier than say 190gr bullets, you will be well served with you 1:11.25 twisted barrel.

Hello everyone, I have just joined this board so that I can talk about .308 ARs with people who have experience with them. I am a long time competition shooter who has pretty much dedicated himself to long range F-TR competitions for the last several years. The .308 Winchester has been my goto cartridge for 30+ years and I handload large quantities of it for 1000 yard competitions. I was a Service Rifle shooter for many years before that and so I am very familiar with the AR-15 family of rifles. I've built several and shot them in various competitions as well as taking them hunting. It was time to bring together my two passions; the .308 Winchester and the AR-15. So I broke down and bought myself an AR-10(T) at the end of last year. Of course, it was not going to remain stock, I wanted to build it up using all my experience with the AR-15 and the long range .308 Winchester. I came up with this: Since that picture was taken I replaced the stock with a PRS and the original grip with the new MagPul MOE: I developed a load for it using a 175gr Nosler bullet and I'm having fun with it. I will post the details of the rifle in the main forum. Regards, Pegasus