Soot on fired factory brass for 450 Bushmaster.

[CJP]

Has anyone her noticed this on your spent brass? My buddy contacted Ruger today to find out why this is happening to the brass coming from his Ruger American Ranch rifle. The Ruger rep said that he possibly had an oversized chamber. The rep suggested that my buddy send in his rifle along with a spent factory case to see if they needed to replace his barrel. Does this happen just in the Ruger bolt action rifles or does it happen in other bolt actions,single shots and in AR platforms. I ask this as I also own a Ruger American with soot on my spent factory brass and wonder if it is widespread or just a few Ruger rifles.

[Ol` Joe]

It happens any time the case doesn't expand quick enough to seal the chamber/case body behind it. The case acts as a gasket and if it is not under enough pressure quick enough it can allow some gas to blow by.

Not really a uncommon event, look at the neck of a fired bottleneck case like the 30-06 or 270 as example and you will often see some fouling too.

[IraqVet1982]

Not an issue, very common with semi autos... but he should probably send me all of his brass for further and continual testing.

[10x25mm]

Maximum chamber pressure of factory loaded .450 Bushmaster is relatively low for a rifle cartridge, about 38,000 psi. This pressure builds slowly in many loads and harder (stronger) neck brass cases do not obturate quickly enough to prevent some leak back. This is what Ol' Joe explained.

Most cartridges operating at 38,000 psi have much thinner neck walls, around 0.010 inch, like .30-30 Winchester. This also reduces the stiffness of the case neck, facilitating obturation. .450 Bushmaster has a 0.015 inch case neck wall thickness to prevent bullet displacement during semiautomatic feeding, similar to the higher pressure .30-06 and 7.62 NATO rounds.

This kind of sooting can be greatly reduced by annealing case necks before reloading.

[coyote wacker]

Has anyone her noticed this on your spent brass? My buddy contacted Ruger today to find out why this is happening to the brass coming from his Ruger American Ranch rifle. The Ruger rep said that he possibly had an oversized chamber. The rep suggested that my buddy send in his rifle along with a spent factory case to see if they needed to replace his barrel. Does this happen just in the Ruger bolt action rifles or does it happen in other bolt actions,single shots and in AR platforms. I ask this as I also own a Ruger American with soot on my spent factory brass and wonder if it is widespread or just a few Ruger rifles.

Is there more "soot" when its colder...it could be the powder that is being used....

Before sending the gun back to Ruger measure fired cases...should measure around .480" at the mouth....

[Melectrok]

Is there more "soot" when its colder...it could be the powder that is being used....

Before sending the gun back to Ruger measure fired cases...should measure around .480" at the mouth....

What was determined about this? I am having the same issue with a Savage Wolverine. Its been in 3 times and they say they dont know what is wrong with it. Using factory ammo.

[BMT85]

What was determined about this? I am having the same issue with a Savage Wolverine. Its been in 3 times and they say they dont know what is wrong with it. Using factory ammo.

10x25mm explained what is happening. It’s the ammo, not your rifle. I’m surprised Savage didn’t tell you this and actually took the rifle 3 times.

[JDG]

You guys would really be disappointed with a blow back 9mm! lol

[Ol` Joe]

What was determined about this? I am having the same issue with a Savage Wolverine. Its been in 3 times and they say they dont know what is wrong with it. Using factory ammo.

It’s a perfectly normal occurrence due to the nature of a low pressure cartridge as mentioned earlier. Savage can’t find anything Wong with the rifle because there is nothing wrong with it. Even high pressure cartridges some a bit of blow back on their necks in some instances.

[Melectrok]

10x25mm explained what is happening. It’s the ammo, not your rifle. I’m surprised Savage didn’t tell you this and actually took the rifle 3 times.

I guess I cant believe they did, and even gave me a replacement rifle in place of it. So I guess I can live with it as long as it is not issue. With all of this rifle exchange they did I even got a bonus misfire issue out of it. Apparently they don't have the brightest gunsmiths there. However I know 2 other people with ruger americans that do have the issue at all. And also if is shoot the Remington ammo I do not get any sooting at all. But I get terrible accuracy with it. I can assume its an ammo issue at this point, but since I still have the missfire issue now its going back right after deer season regardless. I just dont want it to be a chambering issue and let the warranty expire.