McGowen Match Barrel Swap on a Norc M4 = 1/2 min Accuracy

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Mystic Precision

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Due to an unfortunate production ooops, I came to inherit a very nice SS 223 Wylde Chambered, 8 twist, 18.5" SPR AR Drop in Barrel made by McGowen.

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The big "ooops" was the use of a carbine gas port length which the customer most definitely didn't want. Issues with early cycling and torn cases feared, I decided "what the heck" and installed it on my Norc M4 that I have been really enjoying.

I have since seen carbine length gas tubes used on similar and longer length barrels so it is not something unique. Just through us for a bit.

This is the rifle that I had tweaked to soften the recoil down.

Except for swapping in the barrel, everything else is the same. All the internals are orig Norc M4 including the milspec trigger. The recoil spring and buffer had been changed to help reduce the recoil.

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Mounted my trusty Sightron SII Big Sky 36X in Burris XTR high rings and it just cleared the front sight.

Off to the range. My goal to see if I could break the MOA barrier with a milspec rifle and a simple barrel swap.

The bullet used is Sierra 69gr MK, CCI 450 primers, Rem brass (was what I had), and both WCC735 (cheap surplus) and Benchmark (got great results in a mini 14 Target).

Started with WCC735 and it didn't take long to get some promising groups. On a really nice calm cool morning, this was one of the groups at 100yds.

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Then another

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Well, MOA had definitely been cracked.

Then it was benchmark. After cleaning the bore....

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WOW, the first two shots from a clean barrel cut, then the 3rds a bit off but definitely a tight group (measured later at 1/2").

I quickly went to my next load and drilled this nice 1/2"

What really put a smile on my face was each shot had been singled loaded WITHOUT a mag (DUH!!!). So the bolt had to be pulled back and locked and the ammo gingerly stuffed into the chamber. Most ammo was not fully seated before the bolt was dropped.

Each shot was reset on the bags which weren't dead steady like you would set up with a normal rifle stock.

VERY PLEASED - BUTTTTT, a couple of hero groups don't confirm much.

So I loaded up more and off to the range today. Warmer around 12/15C. Light gusty winds with definitely some tail gusts and a bit of cross.

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First 3 shots fired was with another test load and clustered really nicely (A) - later measured at 9/16". The next 3 shots (B) had a higher load and the groups opened up alot.

Letting the barrel cool, I shot (C) which was also shot yesterday for 1/2" 3 rds but didn't do so well today. At least for shot #2 - maybe wind????

Hunkered down for (D) cause this was my best load from last time and it drilled this very nice 4rds hole. #4 shot dissappeared into the 3rd hole. This group measures 7/16".

Yes, confirmed 1/2 min at 100yds with a rebarreled Norc M4. It still has a very heavy factory trigger. I have tuned to get most of the creep out and is now pretty much single stage but WAAAAYYYY heavier then any target rifle should be. It is a fight to get that shot off and I would be surprised that some 'space' between shots is just due to trigger control (or lack thereof).

As for the ejection, it is gentle and lobs the cases a few feet from the port. There is absolutely nothing excessive about the ejection and no different then my factory barrel set up. The cases come to rest in a nice pile 6 to 8 ft from my bench after bouncing on a concrete floor.

Doesn't seem to be any issues using a carbine length gas tube with this barrel and port. I am hopeful that if I ever put in a much lighter trigger and have a steadier rest, I can snuggle up my bullets a bit more but for now, I am thrilled on the performance.

McGowen has certainly produced a great quality barrel and machined to exact dimensions for a drop in fit. Except for the gas port not being in the location desired by the customer, this barrel is a tack driver.

Try and get out to 200yds soon and see how it groups.....

Enjoy...

Jerry
 
beltfed said:
Not surprising results. Pretty common knowledge the barrel is the heart of accuracy on an AR, the rest of it there for the shooter.
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As a precision shooter, the importance of barrels are well understood but AR's are new to me.

After reading articles on rifles offered by all the major US brands, the trend has always been well over MOA accuracy as "good" with the rare bird shooting MOA or sub MOA.

These rifles are usually touted with custom this and that, specially manf to get these results. Their prices certainly reflect that.

I have only seen 2 that even suggested 1/2 min as possible let alone show data to back it up.

So to simply swap barrels on a milspec Norc M4 (wrong gas port and all), loading up some quality ammo, and getting groups 1/2 min at 100yds despite the heavy trigger and less then ideal rests, I am thrilled.... and very surprised.

And makes me wonder, what are you actually buying in these other mega dollar rigs?

Jerry
 
Clobbersauras said:
How much do you want for it?:D

Very good post Sir. Get a good trigger in that thing and a proper stock, then report back!
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Adding a better trigger and stock WILL make it far easier to get consistent groups. Will likely shave up to 1/8" from the 100yds average. I have no illusions on the limitations of this set up. I just dont expect to see 1/4 min consistency but you just never know.

IMR8208 is sitting on the shelf

I am already thrilled by getting to 1/2 min - I was just hoping to get sub MOA.

I am working on a pic rail adaptor so that I can use my MPOD. That will really help with stability especially with the very nice YHM free float tube on the rifle.

Add a rear stock with some provisions for suppport (third leg) and this will be deadly. will see what my new suppliers can offer me.

I am thinking of a Jewell or Timney as I have these readily available.

Overall cost of the project is starting to get into the "pricey" category but there are certainly no complaints on the performance.

And about the only things that would be Norc would be the receiver, upper, buffer tube, and Bolt/BCG :D

Jerry
 
Mystic Precision said:
And makes me wonder, what are you actually buying in these other mega dollar rigs?

Jerry
Click to expand...


For the most part, the difference is simply paying for an American or Canadian work force, rather then chinese child labor.

That being said, Take a Noveske, LMT or Knights and the real difference is also in the craftsmanship and quality control.
 
QC and pension plans aside, I am speaking directly about holes in paper and most of these brands do not report similar performance.

Understood it may be the ammo used but there are alot of very good quality factory ammo yet these type of results do not get reported often. At least, you don't see it in the many AR mags.

Even the many handloaders all over internet land don't report getting sub MOA accuracy on a consistent basis let alone bolt action accuracy.

So what type of barrel are these brands putting in their rifles? Or at least, what type of chambers? 223 Wylde is nothing new and offered on many rigs.

I am sure that this barrel swap improvement would work on any AR platform as there is nothing unique about this Norc

Adding a quality barrel to any of the name brand rifles would certainly raise performance a notch or two and they will look great doing it.

Jerry
 
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