LMT MRP accuracy issue

[bowietx]

Remedial actions taken:


Cleaned barrel and breech face
Used PMAG vice GI mag to limit rocking
Double checked optics mount
Used Irons and EOTECH
Used 75gr OTM bullets

Result: Same thing as before two rounds touching, one round low


Next Action: Replaced barrel w/new 16" LMT MRP

Result: .63 inch group at 50 yards


Get Some!!!


Thank you to all who offered opinions and solutions. Sinister thank you for helping me through the cathartic process of letting the old barrel go and finding solace in a new one.

[krichbaum]

Glad you got it fixed. These MRP barrels shoot, but it's a little disappointing that yours was going downhill with that round count. I guess if it's been run hard though, it's to be expected.

Here's what my nearly new 14.5" MRP barrel was doing the other day with a 4moa Aimpoint Micro:



I should throw a scope on it and see what it can do.

[bowietx]

Nice shooting, MRP will rock the accuracy bell all day. I threw up in my mouth a little and convulsed when I was removing the old barrel, but the new one cured everything!! How do you like the micro on that setup?

[krichbaum]

I like the micro a lot because the MRP needs a little help staying slim and trim. I normally have a 10.5" barrel in my MRP but I picked up this 14.5" barrel (with a pinned muzzle device to get 16") recently and I'm loving it...it has me thinking I should get another MRP CQB chassis so I have the 10.5" setup ready to go too since I love that one as well.

[Iraqgunz]

I am as well to be honest. I need to re-check my 11.5" now because it's had about 3 times that amount through it and it is still running good. But, I also don't get wrapped up in stuff like this.

I'm surprised that a 16" barrel would give up the ghost that quickly. I'll obviously bend to Sinister's experience but I wouldn't think a normal, good barrel like LMT's would wear out that quickly. I could see a 10.5 barrel but not the 16.

[Sticks]

I'm surprised that a 16" barrel would give up the ghost that quickly. I'll obviously bend to Sinister's experience but I wouldn't think a normal, good barrel like LMT's would wear out that quickly. I could see a 10.5 barrel but not the 16.

I am as well to be honest. I need to re-check my 11.5" now because it's had about 3 times that amount through it and it is still running good. But, I also don't get wrapped up in stuff like this.

That makes 3 (or 30) of us. I have 8500+ down the pipe of my centurion CHF 16" middy and my last outing got me this with an Aimpoint PRO, prone off the mag. Shots 3 and 7 I knew were out as soon as I pulled the trigger (Thanks Pat MacNamera).

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[sinister]

Barrel wear is an interesting topic in that many will never, ever shoot out their original barrel.

It becomes more complicated when the guy shooting is a good shot -- he will tend to blame himself before his equipment, masking a drop in on-target performance. "The gun has always shot tight -- I MUST be doing something wrong. People have told me a brand XYZ (or cold hammer forged or whatever) barrel will go 10,000 rounds before going bad."

Barrels are like brass or tires -- eventually they may need to be yanked and thrown away. If you are doing your own maintenance it's a 30-minute job, tops (even hung over).

[steyrman13]

I'm glad you figured out what it was, but it ducks it wasn't an easy fix such as fouling, parallax, non-steady rest. I remember seeing the 5k rnd remark, but thought it to be low for a chrome lined vs stainless barrel. But schedule of firing, ammo, quality of chrome lining,etc all play into the barrel life too.

[T2C]

A barrel is a consumable item like anything else. You should expect some loss in accuracy as the round count increases. If you shoot rapidly enough to really heat up the barrel, wear will accelerate.

When I was still competing in High Power Rifle, I changed barrels every 5,000-6,000 rounds depending on when my scores started to drop without any other explanation. Just because a barrel will shoot well at 300 yards, does not mean it will shoot well at 600 yards.

I sold the used barrels to people who would not know the difference in accuracy with the understanding that they were buying a used barrel. Feedback was that they shot sub MOA groups, but it was from people who never shoot beyond 300 yards.

It's good to hear that you identified the issue and your rifle is shooting solid groups again.

[ALCOAR]

How many other AR rifle designs permit one to use their discarded barrels as practice barrels on the fly....i.e. switch from duty to practice barrel under a minute

The MRP design will allow you to use that diminished barrel a great deal in the future for practice or fun shooting if you so desire given the speed, and ease at which you can go from one barrel to another. Sounds like it still has some use left in it.

5k seems low to me, but as noted by another member above...I always yield to Sinister's word around here, especially on subjects such as this one.