Muzzle crown cleaning

Discussion about rifles in 300 AAC BLACKOUT (7.62x35mm), hosted by the creator of the cartridge.

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wildfowler
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Muzzle crown cleaning

Post by wildfowler »

Quick question, How many suppressed 300blk shooters make a habit of carefully cleaning the baked on carbon from their muzzle crown?

I've observed on one of my rifles that I start to see flyers show up on paper when the buildup starts showing up.

I never paid attention to this until I cleaned my barrel recently. I must have knocked off a "chunk" of carbon from the muzzle because doing so wrecked my accuracy and caused a POI shift.

I decided to carefully clean the entire muzzle to test this. It took Iosso bore paste and a dental pick to get it all off. But sure enough, my accuracy and consistently in grouping came back. No flyers.

Fast-forward a couple hundred rounds and I start to see flyers again. I keep an aerosol can of CLP in my truck and cleaned as best I could which was not as thoroughly but good enough to see the results in paper at the range.

I don't think the carbon will build up the same way if not shooting suppressed or through a muzzle device? The rifle in particular I've been working with has a direct thread suppressor so accessing the muzzle is much easier, but next on my hit list is going to involve my removing an AAC brake mount and cleaning that rifle muzzle as well.

Anyone else ever considered this or made the same observation?

Thanks.
driven every kind of rig that's ever been made, driven the backroads so I wouldn't get weighed. - Lowell George
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rebel
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Re: Muzzle crown cleaning

Post by rebel »

wildfowler wrote:Quick question, How many suppressed 300blk shooters make a habit of carefully cleaning the baked on carbon from their muzzle crown?

I've observed on one of my rifles that I start to see flyers show up on paper when the buildup starts showing up.

I never paid attention to this until I cleaned my barrel recently. I must have knocked off a "chunk" of carbon from the muzzle because doing so wrecked my accuracy and caused a POI shift.

I decided to carefully clean the entire muzzle to test this. It took Iosso bore paste and a dental pick to get it all off. But sure enough, my accuracy and consistently in grouping came back. No flyers.

Fast-forward a couple hundred rounds and I start to see flyers again. I keep an aerosol can of CLP in my truck and cleaned as best I could which was not as thoroughly but good enough to see the results in paper at the range.

I don't think the carbon will build up the same way if not shooting suppressed or through a muzzle device? The rifle in particular I've been working with has a direct thread suppressor so accessing the muzzle is much easier, but next on my hit list is going to involve my removing an AAC brake mount and cleaning that rifle muzzle as well.

Anyone else ever considered this or made the same observation?

Thanks.
Yes, I have. The crown is everything to accuracy. I use a swab and bore cleaner, let it soak and then use both a nylon bore brush and a toothbrush to get the grodue loose. If you wait to long it's a pain.
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Jim Timber
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Re: Muzzle crown cleaning

Post by Jim Timber »

I explicitly designed my muzzle devices to not need a crush washer because of the accumulation of crap on the crown needing to be removed on a semi-regular basis for best performance of the weapon. It's very much a known fact that your crown has a huge impact on the flight of the bullet as it's the junction where the bullet/barrel/gasses all leave one another - last contact before free flight.
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wildfowler
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Re: Muzzle crown cleaning

Post by wildfowler »

In my case, wasn't so much concern with the condition of the crown because the best I can tell it looks like it stays clean. It's the build up of residue around the end of the muzzle.

Maybe it's on the crown and I just can't tell? When I knocked that chunk loose from the end of the barrel it definitely created a shift in impact.

I have two suppressed 308 AR's that don't seem to be affected the same way. If they are it hasn't shown up on paper yet...... ( i'll be paying attention for it)

I know to not let the crown get dinged up which is why I rarely even remove my suppressor and certainly don't take muzzle devices off. I've always thought some sort of muzzle device would be the best way to protect your crown. Little did I know it creates its own problem.

This was a new one on me and I will definitely get in the habit of keeping my crown clean and not let it get to the point where I have to go real aggressive to remove any build up.

Thanks.
driven every kind of rig that's ever been made, driven the backroads so I wouldn't get weighed. - Lowell George
45r
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Re: Muzzle crown cleaning

Post by 45r »

I use a pure copper scrub.
A few twist and crown gtg.
300black
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Re: Muzzle crown cleaning

Post by 300black »

45r wrote:I use a pure copper scrub.
A few twist and crown gtg.

What brand pure copper scrub?


Is this a problem with a muzzle device like the Sig mini-brake under a suppressor?
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Re: Muzzle crown cleaning

Post by ThreeHundredBlackout »

I have a spikes barking spider 2 krink brake on my 8" and when i remove the internals i see the crap build up and that bothers me but i dont think ive ever noticed a poi shift or loss of accuracy. Maybe when i shoot supers it blows enough crap off to keep going without affecting accuracy, idk.
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45r
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Re: Muzzle crown cleaning

Post by 45r »

Choir boy ultimate scrub is what I use.
They work well for cleaning out suppressor tubes also.
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