Hammer Forged Barrel vs. 4150CMV Barrel - QPQ Coated - MPI/HPT

[snackgunner]

Price aside, what are the main differences between these 2 barrel types?

Would one barrel be preferred for certain applications over the other?

Does the Hammer Forged Barrel have a longer life span (round count) as far as accuracy is concerned?

Whats the benefit of the chrome lining over the QPQ Coating?

https://www.bravocompanyusa.com/BCM-...s-11%20bfh.htm

vs

https://dsgarms.com/dsg-4001-0016
https://dsgarms.com/dsg-4001-0007

[titsonritz]

Don't forget the chrome lining on the BCM

[snackgunner]

Don't forget the chrome lining on the BCM

Thanks, updated OP

[grizzman]

Both the BCM and DSG Arms barrels use material from the same family of steel, so there's unlikely to be much of a difference there from a basic material perspective (presuming they are both of equal quality steel).

If it's done correctly on good steel, then the hammer forging process is generally considered to create a longer lasting bore versus other rifling types. The exact improvement in round count over an established firing schedule has not been determined.

The QPQ coating, isn't actually a coating. The structure of the outer surface of the steel is altered, making it harder than the underlying steel. Because this treatment doesn't change the physical dimension dimensions of the bore, it should have less of a negative effect on the bore's uniformity. Some people believe that QPQ, and other Nitride processes, are more durable than hard chrome. Some people believe that hard chrome is more durable than QPQ. Neither group has been found to be correct so far.

There are a few exceptions, but if accuracy is more important than durability, then a Nitride treated barrel is generally preferred.


None of the above are referencing the barrels linked to above. An outstanding button rifled 4150CMV barrel will out shoot and out last a mediocre hammer forged 4150CMV barrel. There's a LOT more to the equation than material and interior treatment.

[snackgunner]

Both the BCM and DSG Arms barrels use material from the same family of steel, so there's unlikely to be much of a difference there from a basic material perspective (presuming they are both of equal quality steel).

If it's done correctly on good steel, then the hammer forging process is generally considered to create a longer lasting bore versus other rifling types. The exact improvement in round count over an established firing schedule has not been determined.

The QPQ coating, isn't actually a coating. The structure of the outer surface of the steel is altered, making it harder than the underlying steel. Because this treatment doesn't change the physical dimension dimensions of the bore, it should have less of a negative effect on the bore's uniformity. Some people believe that QPQ, and other Nitride processes, are more durable than hard chrome. Some people believe that hard chrome is more durable than QPQ. Neither group has been found to be correct so far.

There are a few exceptions, but if accuracy is more important than durability, then a Nitride treated barrel is generally preferred.


None of the above are referencing the barrels linked to above. An outstanding button rifled 4150CMV barrel will out shoot and out last a mediocre hammer forged 4150CMV barrel. There's a LOT more to the equation than material and interior treatment.

Thanks for the quality post.

What exactly did you mean by durability ?

And what else is taken into the equation besides barrel material and interior treatment?

[grizzman]

By durability I meant the number of rounds fired before throat erosion reduced accuracy to an unacceptable level.

The method by which the rifling is created is a factor, as well as how well it is implemented. I'm not going to guarantee the absolute accuracy of any of the below, as I've never worked in the barrel creating business.

Krieger's single point cut rifling is highly regarded. Some believe that this method allows for the most precise creation of the lands/grooves in the bore. There aren't many barrel manufacturers that use this method, likely due to the required time and therefore cost (and knowledge). If Krieger were to start using the button rifling process, while continuing their hand lapping and additional quality control inspections, these barrels will likely end up very close to the same precision of lands/grooves/smoothness as their cut rifled barrels. Some other company can also use the single-point cut rifling process to create absolute garbage.

Savage uses the button rifling process, in which a rifling/shaped cutting head (the button) is pulled through the barrel, likely many times to incrementally cut the grooves. Their barrels are also highly regarded, from a factory barrel perspective, even though the complete rifles can cost less than a Krieger barrel. The means by which the barrel is attached to their bolt action rifles is also important to the final accuracy of the rifle, but that's way beyond the scope of this AR-centric thread. They have obviously worked out the fine details of what it takes to use this particular process to create accurate rifling, as well as appropriate QC standards.

Inspection of the bore and the cutting tools is also important to ensure that the bore is as smooth and uniform as possible. If the cutting tool is beyond it's service life, and it is continued to be used, the rifling will continue to be cut, but not to the precision as is they were in perfect condition. Visual and mechanical inspection is important to ensure that the rifling was cut properly.

The bottom line is that the steel used, rifling method, lining/treatment process, hand or fire lapping, air gauging, visual inspection, etc all affect the end product.

I have no experience with DSG Arms, but my BCM hammer forged, BCM non-hammer forged, FN hammer forged, Colt non-hammer forged, etc barrels are all more accurate than would be considered acceptable in a bolt action hunting rifle 50 years ago.

I've read many many times that stainless barrels are more accurate than CMV barrels. This is most likely because stainless steel is easier to cut than CMV, therefore it's easier to do well...not necessarily a better material.

[grizzman]

My answer to the poll is......a 4150 CMV Hammer Forged Barrel....for an SD ready AR.

[JediGuy]

I've read many many times that stainless barrels are more accurate than CMV barrels.

I thought this was more due to the consistent placement of shots over a longer period of time, before the stainless opened up “all at once,” as opposed to chrome lining which gradually demonstrates eroding consistency over its life. That’s a question framed as a statement, I welcome correction.

[grizzman]

I thought this was more due to the consistent placement of shots over a longer period of time, before the stainless opened up “all at once,” as opposed to chrome lining which gradually demonstrates eroding consistency over its life. That’s a question framed as a statement, I welcome correction.

This is another aspect that I considered including, but decided I've likely gone too far without it. I think it's a combination of the two.....more precisely cut rifling (while possibly using more pedestrian methods and QC) and a more consistent performance throughout most of the lifespan.

It isn't just chrome lining that's supposed to slowly erode, especially at the throat, causing a taper in overall barrel accuracy. Non-chrome lined CM barrels apparently exhibit this same trait.

[ABNAK]

Looking at the choices you put forth, I see that there is a $90 difference in price. Not being accusatory, but "cheaping out" is what the DSG seems like. The BCM is a hammer forged, chrome-lined barrel. It costs more, but there is a reason for that.

My personal opinion is that the modern wave of nitride/Melonited barrels is a cost-cutting, cheapskate way for manufacturers to make barrels. Don't get me wrong, I would readily take a nitride/Melonited barrel over an untreated one, but NEVER over a chrome lined one. Just my opinion and worth what you paid for it!