Mossberg receiver

Romulus · February 7, 2001, 02:30 AM

I have a barely used Mossberg (a gift) that needs a new bolt. I was told that replacing the bolt should be done by the factory for headspace reasons. Is this true?

I would like to refinish the receiver with a matte laquer or other non-reflective finish. Is the factory finish some sort of hard-anodizing that should be left alone? How would I get a new non-reflective finish to adhere to the slick anodized receiver? I would like to parkerize the piece and find a matching finish for the non-parkerizable receiver.

Begging for some ideas...

George Stringer · February 7, 2001, 09:53 AM

Romulus, a different bolt can and usually does change the headspace. I really don't know what finish was used on your gun. George

Romulus · February 7, 2001, 10:51 AM

It's the standard factory finish on the alloy (yuck!) receiver. Glossy (not high-gloss) blue-black...

Can the strength of the receiver be affected if this finish were removed - I mean, is it like hard-anodizing, which plays a role in surface tension and thus strengthens the alloy - in which case I wouldn't touch it.

Or is the finish merely aesthetic...

Keith J · February 7, 2001, 10:35 PM

HA does not affect the strength of the part provided the aluminum isn't over-aged at high (anything over 250 F) temps. Only bead-blasting or shot-peening improve surface toughness by residual compressive skin stress. HA is mighty brittle stuff and its tensile strength isn't something to be relied upon.

If you want to use an epoxy lacquer, degrease the anodization and leave it. Its an excellent substrate for most coatings. If you do reanodize it, specify no sealing or post anodization conversion treatment if you are going to coat. Also look int Robar or any of Whitford's Xylan treatments. You will have to find a coater specializing in this as these aren't generally sold to the public. HA + Xylan is good enough for 6061 T6 aluminum in the subsea (10,000 feet below the surface)environment. Its fine on any gun.

Why does the bolt need replacing? I doubt one can get a replacement and Brownell's doesn't stock it. I'm pretty sure a Mossberg is fitted, not measured like the AR15.

Romulus · February 8, 2001, 12:31 AM

Keith J, I got the shotgun w/ out bolt. A local gunsmith said that replacing the bolt would be a factory job. Mossberg (I believe in their good faith) confirmed that.

Thanks for the primer on HA...I will proceed as you suggest. Now I'll just have to find a coating that blends well with a parkerized barrel...

Keith J · February 8, 2001, 09:24 PM

So I guess you are going to OF Mossberg for a bolt. As far as the best finishes, Robar cannot be beat. Their polymer coatings (I think they use Whitford products)can be had in almost any shade you want and their nickel finishes are out of this world. Here's their link:

http://www.robarguns.com/

I recommend these for a first rat job. If DIY is what you want, try Brownells Aluma-Hyde II. Its an epoxy finish available in many shades like Parkerized gray, matte black, OD green and earth brown.

This is the only low temp curing epoxy they have. All others require 325 F curing which can overage aluminum.

BTW, I am not joking about the aluminum. The receiver isn't too highly stressed but overaging will damage it. I have heard of some fools refinishing aluminum SCUBA tanks with powder coating. They baked them at 350 F......on the next fill, the tanks ruptured, killing two with a double blast, one going off as a response to the other. It was like a grenade.

Romulus · February 8, 2001, 11:17 PM

Keith J,

Are you a metallurgist? Most fascinating field, and your disquisition on aluminium alloy and "overaging" perils makes me loathe the material even further...it's ugly, and it is the most frequently spec'd material in my business - loathing can be summed up by the simple formula of : ugliness x frequency of exposure to such ugliness.

The firearm is worth saving though, it will make a nice little car companion.

Thanks again for your input - quite valuable...

Romulus · February 10, 2001, 07:22 PM

What about a cast aluminum pressure-cooker, it sits on a flame that must be higher than 350 degrees...What keeps them from overageing and exploding?

February 7, 2001, 10:35 PM	#4
Keith J Senior Member Join Date: December 15, 2000 Posts: 469	Hard anodization? HA does not affect the strength of the part provided the aluminum isn't over-aged at high (anything over 250 F) temps. Only bead-blasting or shot-peening improve surface toughness by residual compressive skin stress. HA is mighty brittle stuff and its tensile strength isn't something to be relied upon. If you want to use an epoxy lacquer, degrease the anodization and leave it. Its an excellent substrate for most coatings. If you do reanodize it, specify no sealing or post anodization conversion treatment if you are going to coat. Also look int Robar or any of Whitford's Xylan treatments. You will have to find a coater specializing in this as these aren't generally sold to the public. HA + Xylan is good enough for 6061 T6 aluminum in the subsea (10,000 feet below the surface)environment. Its fine on any gun. Why does the bolt need replacing? I doubt one can get a replacement and Brownell's doesn't stock it. I'm pretty sure a Mossberg is fitted, not measured like the AR15.

February 8, 2001, 09:24 PM	#6
Keith J Senior Member Join Date: December 15, 2000 Posts: 469	No bolts out of Brownells So I guess you are going to OF Mossberg for a bolt. As far as the best finishes, Robar cannot be beat. Their polymer coatings (I think they use Whitford products)can be had in almost any shade you want and their nickel finishes are out of this world. Here's their link: http://www.robarguns.com/ I recommend these for a first rat job. If DIY is what you want, try Brownells Aluma-Hyde II. Its an epoxy finish available in many shades like Parkerized gray, matte black, OD green and earth brown. This is the only low temp curing epoxy they have. All others require 325 F curing which can overage aluminum. BTW, I am not joking about the aluminum. The receiver isn't too highly stressed but overaging will damage it. I have heard of some fools refinishing aluminum SCUBA tanks with powder coating. They baked them at 350 F......on the next fill, the tanks ruptured, killing two with a double blast, one going off as a response to the other. It was like a grenade.

February 10, 2001, 07:22 PM	#8
Romulus Senior Member Join Date: January 18, 2001 Location: Kettle Moraine country Posts: 897	just thought of something... What about a cast aluminum pressure-cooker, it sits on a flame that must be higher than 350 degrees...What keeps them from overageing and exploding?

February 7, 2001, 02:30 AM	#1
Romulus Senior Member Join Date: January 18, 2001 Location: Kettle Moraine country Posts: 897	I have a barely used Mossberg (a gift) that needs a new bolt. I was told that replacing the bolt should be done by the factory for headspace reasons. Is this true? I would like to refinish the receiver with a matte laquer or other non-reflective finish. Is the factory finish some sort of hard-anodizing that should be left alone? How would I get a new non-reflective finish to adhere to the slick anodized receiver? I would like to parkerize the piece and find a matching finish for the non-parkerizable receiver. Begging for some ideas...

February 7, 2001, 09:53 AM	#2
George Stringer Staff Alumnus Join Date: October 12, 1998 Location: Earlington KY Posts: 2,299	Romulus, a different bolt can and usually does change the headspace. I really don't know what finish was used on your gun. George

February 7, 2001, 10:51 AM	#3
Romulus Senior Member Join Date: January 18, 2001 Location: Kettle Moraine country Posts: 897	It's the standard factory finish on the alloy (yuck!) receiver. Glossy (not high-gloss) blue-black... Can the strength of the receiver be affected if this finish were removed - I mean, is it like hard-anodizing, which plays a role in surface tension and thus strengthens the alloy - in which case I wouldn't touch it. Or is the finish merely aesthetic...

February 8, 2001, 12:31 AM	#5
Romulus Senior Member Join Date: January 18, 2001 Location: Kettle Moraine country Posts: 897	Keith J, I got the shotgun w/ out bolt. A local gunsmith said that replacing the bolt would be a factory job. Mossberg (I believe in their good faith) confirmed that. Thanks for the primer on HA...I will proceed as you suggest. Now I'll just have to find a coating that blends well with a parkerized barrel...

February 8, 2001, 11:17 PM	#7
Romulus Senior Member Join Date: January 18, 2001 Location: Kettle Moraine country Posts: 897	Keith J, Are you a metallurgist? Most fascinating field, and your disquisition on aluminium alloy and "overaging" perils makes me loathe the material even further...it's ugly, and it is the most frequently spec'd material in my business - loathing can be summed up by the simple formula of : ugliness x frequency of exposure to such ugliness. The firearm is worth saving though, it will make a nice little car companion. Thanks again for your input - quite valuable...