barrel life?

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Rich Coyle
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barrel life?

Post by Rich Coyle » Sun Sep 11, 2016 4:05 pm

What can one expect from a 300 BO barrel running supersonic and the same question for running subsonic?

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gds
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Re: barrel life?

Post by gds » Sun Sep 11, 2016 4:13 pm

I wore one out in less then 4000 rounds 90% of those subs.

However I think I had a defective barrel. Which is why I will not recommend Black hole weaponry barrels.

I have at least that many plus on another barrel with no issues. mix of subs and supers.

Frankly I would say there are too many variables to give a accurate answer.
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Alphawolf082
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Re: barrel life?

Post by Alphawolf082 » Sun Sep 11, 2016 7:31 pm

It seems that a like for like barrel would last longer than .223 since the neck isnt tapered nearly as much. I have a colt 5.56 barrel with well over 10k down it that still groups ~1" @100y.

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Re: barrel life?

Post by Whole Bunches » Mon Sep 12, 2016 12:09 pm

See my post in Main Discussion Area. While I'm not specifically testing subsonic vs supersonic, I'm not seeing any difference in bbl life jump out at me with bbls that get more subsonic than supersonic fired from them. It could be that my subs are normally the longer bearing 220gr bullets so the longer bearing surface wears just as much as a shorter bearing surface, but faster going supersonic bullet. And, anyway you load it, the Blackout just doesn't use much powder compared to "conventional" hunting 30 caliber cartridges like .308, 30-06.

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Re: barrel life?

Post by A-Game » Thu Sep 15, 2016 7:26 pm

The manual for an AAC MPW rifle has the following list on page 26:
http://300aacblackout.com/resources/AAC-AR-Manual.pdf

Recreational use: 50,000
Competition use: 35,000
Mission Critical: 20,000

It is a 4150 button rifle barrel that is Nitrided (Case Hardended)

It does not have chrome lining.
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Whole Bunches
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Re: barrel life?

Post by Whole Bunches » Thu Sep 15, 2016 9:30 pm

A-Game wrote:The manual for an AAC MPW rifle has the following list on page 26:
http://300aacblackout.com/resources/AAC-AR-Manual.pdf

Recreational use: 50,000
Competition use: 35,000
Mission Critical: 20,000

It is a 4150 button rifle barrel that is Nitrided (Case Hardended)

It does not have chrome lining.
VERY interesting. I need to get busy and shoot more to get more data on bbl wear!

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Re: barrel life?

Post by Rich Coyle » Sat Sep 24, 2016 1:03 pm

Whole Bunches wrote:
A-Game wrote:The manual for an AAC MPW rifle has the following list on page 26:
http://300aacblackout.com/resources/AAC-AR-Manual.pdf

Recreational use: 50,000
Competition use: 35,000
Mission Critical: 20,000

It is a 4150 button rifle barrel that is Nitrided (Case Hardended)

It does not have chrome lining.
VERY interesting. I need to get busy and shoot more to get more data on bbl wear!
I guess since I am using sub-sonic loads for hunting coyotes this barrel will last 'til Jesus comes. :P

iplaywithnoshoes
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Re: barrel life?

Post by iplaywithnoshoes » Wed Jan 18, 2017 3:20 pm

There is a nice worksheet here which summarizes most of the variables involved. You can download it here:

http://www.accurateshooter.com/technica ... rrel-life/

It basically boils down to the effective chamber pressure, specific energy of your chosen powder, amount of powder used and the bore diameter. The worksheet doesn't take barrel heat, barrel and projectile material into account but if you keep the barrel temps reasonable these are decent estimates.

Example of one of my sub loads: 208gr ELD-X, 11.0gr H4198, 0.020" jump, estimated 25,000CUP. That apparently gives me 136K shots (yeah right...) The barrel heats up considerably from shot to shot though so it's likely closer to 50K rounds before the muzzle starts to fishmouth and throat needs to be chased a bit.

One supersonic one I use: 150gr HDY FMJBT, 15.0gr H110, 0.020" jump, estimated 36,000CUP. About 50K rounds with cooling. Probably cut that in half with heating. With a max load of 17.2gr, you are at 21,000 rounds. Either way you slice it, you will be in the 5 digit realm of rounds down the barrel if you don't purposely cook the tube.

[Note:These are technically not published loads. Powder charges are within range of Hodgdon's manual but the ELD-X is not a listed projectile: for that reason I have not listed COAL. You must tailor that to YOUR setup, since seating depth can drastically change pressure or cause a compressed loading condition, which can be dangerous.)

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Re: barrel life?

Post by cmcleod » Wed Feb 01, 2017 8:33 pm

If can ever spend enough money in ammo to wear out a barrel, I can probably afford a new barrel...

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Dr.Phil
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Re: barrel life?

Post by Dr.Phil » Thu Feb 02, 2017 10:23 am

One factor to consider with 300 BLK is also powder selection.
Powders like Lil' Gun are quite a bit hotter burning than powders such as VV.
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