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11/9/2018 9:21:38 PM
Posted: 6/20/2018 7:36:10 AM EST
[Last Edit: 6/20/2018 7:41:29 AM EST by BassFishing]
Greetings,

I'd like to get your input please, if you have time. I have the Rock River national match AR15 (5.56 mm). It has the 20" stainless match barrel. I just got this rifle and it only has 300 rounds through it yet. I'm new to high power rifle. I shot one CMP XTC match and it was very fun. I came in last place but it was still fun. I was talking to someone at the gun club who said the barrel will need to be relaced after 3000-4000 rounds because it will be shot out. What if I don't replace it? I have 200 rounds through it just from two range practice sessions, so my barrel is going to be shot out fast by that logic.
But what if I just keep shooting with it? Will I still be competitive in a match or is it going to be totally impossible to call my shots or to win? I am just a beginner, so does it really matter at my skill level? I don't understand how a barrel can be shot out after 3000 rounds. Maybe it would only show at the 600 yard line? That is the hardest part of the course for me. These CMP high power rifle matches require us to fire at 200, 300, and 600 yards.
Maybe the 200 and 300 yard line would not be a problem with an old barrel, but 600 may be?
Thank you!
Link Posted: 6/20/2018 12:48:08 PM EST
Serious competitors switch barrels faster than others. If all you want is 1/2 MOA groups, then you might need to switch them out that fast. I've only had 1 barrel open up. It was a DPMS stainless MK12 barrel on my 3 gun AR. It was a solid 1 MOA barrel for 6000-7000 rounds then over that last season opened up to 2 MOA. For 3 gun, I wasn't too worried about until I was struggling to hit 60% silhouettes at 400 yards.

If you are a casual competitor, I wouldn't stress about it. Keep a round count, check groups at 100 yards a couple times a year and record it. When you see the groups open up, re-barrel. Changing a barrel is easy and not terrible expensive.

Use this barrel as a training tool. As your skills improve and you shoot more often, you will want to change your metrics.
Link Posted: 6/20/2018 1:23:40 PM EST
[Last Edit: 6/20/2018 1:54:02 PM EST by Sinister]
A National Match rifle will of course continue to shoot. Put ammo in it, squeeze the trigger, and the bullet will fly through the air and the action will function.

As far as precision, the throat of the barrel typically advances .001 inch for each thousand rounds you fire. Gases start to blow-by the bullet as it makes the jump to the leades of your rifling and groups start to widen.

As you get closer to wear-out this typically manifests itself as groups at 300 yards with separate, distinct group centers (three or four bullet holes here, a few there, some outlying fliers). You'll be frustrated as you try to correct the center of your groups into the X-ring and your adjustments don't make sense.

At 600 yards you'll start to get un-called 9s and the occasional 8 from out of nowhere. You'll be ticked-off at yourself for not catching wind switches when in reality you are experiencing varying muzzle velocities (giving different vertical variation, and different wind effect horizontally).

The Army re-barrels between 2,500 and 3,500 rounds as X-counts drop (as tracked by the shooter's average score). Stainless barrels seem to stop grouping well quickly, while chro-moly barrels seem to hang in there longer with slowly declining precision.

The Army Team issues each rifle shooter 5 uppers and each Soldier is expected to keep up with his respective round counts. Typically one for practice and local matches, one for the Interservice and Nationals, and a spare for when one needs to go back to the Shop for a new barrel. One for the Infantry Trophy (rapid-fire) "Rattle-Battle" match. One for 1,000-yard matches.

The average weekend recreational competition shooter (especially a good one) will blame himself for deteriorating performance and scores (since he's obviously read on ARFCOM he can get 5,000 to 10,000 rounds from a precision-made cut-rifled barrel) instead of lining up his next barrel with his gunsmith.

Compass Lake's NM barrel has a short throat that is excellent at 200 and 300 yards. The Wylde chamber accommodates a slightly longer throat for 80-grain Match Kings, while the Army throat is the longest since they have to monitor barrel wear and performance on up to 105 or more uppers a season (depending on how many troops and tryouts are picked up for the Summer Team).
Link Posted: 6/20/2018 1:32:57 PM EST
[Last Edit: 6/20/2018 1:54:59 PM EST by BassFishing]
Thank you for that information. I wish I were on the Army team and had five uppers issued to me. But I am nowhere near good enough to compete at their level. I shot a 320/500 at the last EIC match.

Do you think EIC rifle competition is easier than EIC pistol? I think it might be. With pistol, you can only hold with one hand, and I get nervous and jittery and my hand shakes. That isn't a problem with rifle since I'm holding it with both arms.
Link Posted: 6/20/2018 10:03:18 PM EST
[Last Edit: 6/21/2018 2:21:06 PM EST by HighpowerRifleBrony]
Granted I use moly'd bullets, but I've got a DPMS with 5800 rounds that can clean the MR-31 with my usual short range load, but it seems a bit off call. I can no longer see the leade with the naked eye.
Another DPMS with 4600 that's still humming to at least 300yds. Still some leade.
An RRA with 2200 that wrecks the X, but it's in an A2 I'm preserving.

While more challenging, I've been using my carbine with chromelined .gov profile 1:7 (measured at 7.7). Happens to shoot as well as the others, but should last a while longer without worry.

I've had a borrowed Noveske (Pac-Nor) shoot out in under 2000. Fine at the State Champs and crapped out at Camp Perry.

There's a fellow in central/southern TX with a nitrided Shilen that I last heard had 8000 and was going strong.

Whether the bullets are bare or coated, get a spare barrel at 3000. If you get serious, change it before the next big match.

I don't recall the minimum scores and respective difficulty, but rifle has more "Leg meat" so I say that's enough to be easier.
Link Posted: 6/21/2018 12:51:34 PM EST
Most of the replies have been spot on. Reality is most of us will pull and sell a typical NM barrel at around 3000 rounds. I've got a few of those Shilen BBL's malonited BBL's that I'm still experimenting with, and intend to run up to 6000 rounds; but I'm not going to break 3000 rounds on it until after Camp Perry this year. A used NM barrel will sell for close to $100 or more at that round count, which helps finance its replacement barrel.

If you keep shooting that RRA past 3000 rounds, you won't see any difference until you get past the 300 yard line. In my observation, a "shot out" barrel will shoot magazine-length spec ammo just fine for several thousand more rounds, particularly at 200 and 300 yard lines, but even at 600 yards a lot of times. A lot of NTIT (rattle battle) barrels are NM bullseye barrels past 3000 rounds, and just cycled to NTIT service, where they continue to be serviceable.

I suspect that the 80 gr bullet profile is just less tolerant to barrel erosion, than the more typical 77 gr and other shorter magazine length profile bullets. That, and it takes distance for the oddities such as warble, inconsistent velocity, or other factors to start to show up. A shot-out NM barrel can shoot like a dream with light bullets at 100 yards long all day; which is why you're able to sell a "shot out" (to us BBL) to someone, and them be happy as a clam with tight groups with it, since most people only shoot 100-200 yards anyway.

For added data - I was at a match this season where a Jr shooter was lighting it up at 200 and 300 yards; she was really doing well, with clean targets. Then at 600 yards, it all completely tanked. Shots were barely in the black. We're not allowed to coach while score-keeping (NRA rules), so I had to just watch (painful). The next day at the leg-match, she borrowed someone else's rifle. And her 600 yard scores were dramatically better. After that, questions started being asked about her BBL. Turns out, it had over 5000 rounds, and you could visibly see a lot of erosion and only very light rifling.
Link Posted: 6/21/2018 5:26:09 PM EST
My 20" Krieger lost 60 fps around 3000 rounds. By 3500 it was at 80 but still accurate.
Link Posted: 6/21/2018 8:32:57 PM EST
Thank you again. But I noticed that you mentioned 77 gr and 80 gr bullets. I decided that I was only going to load one bullet weight for simplicity. I handloaded 1000 rounds of ammo with LC brass, Rem 7-1/2 primers, 24 gr RL15 powder and the Hornady 75 gr BTHP bullets. Do you think those are good enough for the 600 yard line?
Link Posted: 6/21/2018 11:43:29 PM EST
Yes.
Link Posted: 6/21/2018 11:50:56 PM EST
...but you have to really be on the ball with your wind calls. You can take the 75s to 1,000 when the barrel's newer and in good shape.
Link Posted: 6/22/2018 2:56:34 AM EST
320/500.

I think it'll be a while before he needs 90gr VLDs.
Link Posted: 6/22/2018 3:01:47 AM EST
Yes, I'm really just a beginner. I've heard of the VLD bullets but I didn't know anyone used 90 grain bullets in 5.56. That's a heavy bullet. I think at my current skill level, what I really need is snap-in dry fire practice and just the experience of going to more matches. Thanks for helping me out with all my questions.
Link Posted: 6/22/2018 6:59:38 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By BassFishing:
Yes, I'm really just a beginner... I think at my current skill level, what I really need is snap-in dry fire practice and just the experience of going to more matches. Thanks for helping me out with all my questions.
View Quote
You've figured it out. I'm sure you'll develop very quickly and have lots of fun doing it.

I found the journey itself to Distinguished and The President's as rewarding as actually attaining it -- and met and shot with hundreds of really good, nice people on the way!
Link Posted: 6/23/2018 11:39:39 AM EST
The USAMU rebarrels every 3000 rounds as a preventative maintenance measure. They're trying to place 1st on the national stage and an ounce of protection is worth a pound of cure.

You can safely bet on 5,000 accurate (at 600 yards) rounds through any match grade barrel. That same barrel will still shoot great at 200/300 for practice sessions. It will probably still shoot better than most new chrome lined barrels.

Clean it and keep it lubed and don't do any magazine dumps and it will last a very long time. At least 10,000 total rounds with the last 5,000 being a fun gun.
Link Posted: 6/24/2018 8:44:15 AM EST
Link Posted: 6/28/2018 4:11:42 PM EST
[Last Edit: 6/28/2018 4:13:23 PM EST by Sinister]
We had a guy shooting an M16 with a barrel made from a Wilson blank. That rifle was unbeatable to 1200 rounds -- then the wheels came completely off as if he were throwing 5.56mm bullets downrange, underhand.
Link Posted: 7/1/2018 5:20:25 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Sinister:
We had a guy shooting an M16 with a barrel made from a Wilson blank. That rifle was unbeatable to 1200 rounds -- then the wheels came completely off as if he were throwing 5.56mm bullets downrange, underhand.
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Did he try JB Bore Paste and Kroil or Sweets to clean it thoroughly?
Link Posted: 7/2/2018 1:36:54 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By borderpatrol:

Did he try JB Bore Paste and Kroil or Sweets to clean it thoroughly?
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Sounds like a soft barrel that eroded quickly, similar to the Pac-Nor.
Link Posted: 7/6/2018 9:50:28 PM EST
Has anyone had success with Tubb's Final Finish bullets ever reviving a barrel for an appreciable additional round count before it "went bad" again?

The theory of smoothing out a rough throat sounds like it should make sense but the act of firing abrasive bullets down the bore doesn't exactly make the rifling sharper.
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