Lothar Walther Barrels.

[R.G.C]

Thanks.
I have to say that we have found the wear characteristics of 17-4 PH in H900 condition to be excellent in muzzle brake applications.

Sorry, I did not envisaged this kind of application. I have no real experience in this fiels but presume the vear is caused for most bu blasting particles abrasion with heat added? Is PVD nitride coating or one of the stellites insert at critical place not a solution?

R.G.C

[AR15]

Yes the wear is abrasive and heat related.
Through hardening seems to yield the best results for us as the original bore diameter is retained for longer and the brake operates efficiently for longer because of that. The majority of wear is very close to the bore section on the baffles. If the bore increases in diameter through wear then it obviously becomes less effective.
Nitriding and Vapor Deposition finishes are great but through hardening underneath that to 45Rc approx or higher seems to give the best service life for us.
PVD had some hole penetration issues too, I think the approx rule is twice the diameter of the hole in depth for good deposition, it tapers off from 1-7 diameters as I understand it.

[R.G.C]

Yes the wear is abrasive and heat related.
Through hardening seems to yield the best results for us as the original bore diameter is retained for longer and the brake operates efficiently for longer because of that. The majority of wear is very close to the bore section on the baffles. If the bore increases in diameter through wear then it obviously becomes less effective.
Nitriding and Vapor Deposition finishes are great but through hardening underneath that to 45Rc approx or higher seems to give the best service life for us.
PVD had some hole penetration issues too, I think the approx rule is twice the diameter of the hole in depth for good deposition, it tapers off from 1-7 diameters as I understand it.

AR15
What kind of steel you use then? You mentioned 17-4 PH ? I would think of a tool steel really wear resistant such as those used for injection nozzles and punches and hardening well over 45HRC (54-56).

I continue to think a shouldered Stellite insert pressed in from Inside would considerably extend the life.....and be reolacable and adaotable to calibre?

In my humble ignorace.
R.G.C

[R.G.C]

Yes the wear is abrasive and heat related.
Through hardening seems to yield the best results for us as the original bore diameter is retained for longer and the brake operates efficiently for longer because of that. The majority of wear is very close to the bore section on the baffles. If the bore increases in diameter through wear then it obviously becomes less effective.
Nitriding and Vapor Deposition finishes are great but through hardening underneath that to 45Rc approx or higher seems to give the best service life for us.
PVD had some hole penetration issues too, I think the approx rule is twice the diameter of the hole in depth for good deposition, it tapers off from 1-7 diameters as I understand it.

AR15
What kind of steel you use then? You mentioned 17-4 PH ? I would think of a tool steel really wear resistant such as those used for injection nozzles and punches and hardening well over 45HRC (54-56).

I continue to think a shouldered Stellite insert pressed in from Inside would considerably extend the life.....and be reolacable and adaotable to calibre?

In my humble ignorace.
R.G.C

AR15
In addition:

And what about local stellite plasma deposirion? Would necessitate a refinishing on internal grindr, but perhaos wortg?
From an ignorant again
R.G.C

[AR15]

We have had great success with 4140 to 45Rc and 17-4 too. Abrasive wear to front baffle face but good hole integrity after many 1000 rounds.
Always interested in material suggestions :) The US standard for brakes is 17-4 right now, most companies are using it, but if you think there is something better we could look at please IM me.
I like the insert idea!. We have to keep an eye on production cost and also overall size of the part (length, diameter) though.

[AR15]

Yes the wear is abrasive and heat related.
Through hardening seems to yield the best results for us as the original bore diameter is retained for longer and the brake operates efficiently for longer because of that. The majority of wear is very close to the bore section on the baffles. If the bore increases in diameter through wear then it obviously becomes less effective.
Nitriding and Vapor Deposition finishes are great but through hardening underneath that to 45Rc approx or higher seems to give the best service life for us.
PVD had some hole penetration issues too, I think the approx rule is twice the diameter of the hole in depth for good deposition, it tapers off from 1-7 diameters as I understand it.

AR15
What kind of steel you use then? You mentioned 17-4 PH ? I would think of a tool steel really wear resistant such as those used for injection nozzles and punches and hardening well over 45HRC (54-56).

I continue to think a shouldered Stellite insert pressed in from Inside would considerably extend the life.....and be reolacable and adaotable to calibre?

In my humble ignorace.
R.G.C

AR15
In addition:

And what about local stellite plasma deposirion? Would necessitate a refinishing on internal grindr, but perhaos wortg?
From an ignorant again
R.G.C

Production cost possible too high for the max price the product can be sold for? But very interesting... Some stellite plasma deposirion research is in order for me now :)

[R.G.C]

We have had great success with 4140 to 45Rc and 17-4 too. Abrasive wear to front baffle face but good hole integrity after many 1000 rounds.
Always interested in material suggestions :) The US standard for brakes is 17-4 right now, most companies are using it, but if you think there is something better we could look at please IM me.
I like the insert idea!. We have to keep an eye on production cost and also overall size of the part (length, diameter) though.

AR15,
4141,construction steel, would not for me be the right choice as it hardens low and I is prone to warping under HT.
Should I had to meke a brake, I would go to a high characteristics tool steel:
--Werkstoff Number = 1.2767
--E-Norm = 45NiCrMo16.
-TKM (Thyrodur)2767.
-AISI 6F7. Bohler K600
High Cr and Mo content.
Hardens to 54+, is wear resistant, totally exempt of warping and is the highest wear and impact resistant of all the tool steels. Pplishes well.
Ah, I forgpt: machines easily.
R.G.C

[AR15]

Thank you RGC.
I will look at these.
17-4 is our current material. 4140 is indeed 'old school', it is still used in the USA for this application. Although overtaken by 17-4 now.

[R.G.C]

Thank you RGC.
I will look at these.
17-4 is our current material. 4140 is indeed 'old school', it is still used in the USA for this application. Although overtaken by 17-4 now.

4140 (our 42CrMo4) and 4340 are the most used in US firearms construction. This not necesssarily mean Superior qualities!!!
Compositions:
4140: C=0,42% , Cr=1% , Mo=0,5%
42NiCrMo16: C=0,42% , Ni= 4% , Cr2% , Mo1%
Neat difference in the cost as well but one is plain low alloyed construction steel, while the second is high alloyed tool steel.

R.G.C

[Fedaykin]

Run in ?

Don't start us on that owd chestnut, ooman ! A properly made barrel requires no running in. A barrel that requires running in hasn't been made right !

It's not the barrel but the leade that needs running in. No matter how good your reamer, no matter how good the machinist, when the chamber is cut the lead will have machining marks. Look at these with a boroscope and they look like the teeth on a b****** file. It is these marks that you are evening out/removing by running in your barrel. This is the area that will attract most fouling if not done properly.
Are you really going to tell the likes of Krieger, Bartlein, Obermeyer etc that they are wrong and that the advice they give to their customers is bull.
I know who and what I believe and you are not a one of them. I trust my barrel makers,I trust my machinist/rifle smith. I don't trust striped mono-chrome mammals, who have no pedigree.

Ah I feel like pulling out a deck chair cracking open a cool beer, a packet of peanuts and sitting back to watch the fireworks....

Nothing like the barrel run in argument alongside the clean or not to clean...