Hammer Forged versus Cut Barrels


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Highcaliber
May 16, 2010, 08:30 PM
I'd like some opinions on Hammer forged rifle barrels versus "Cut" barrels.
I know that most, if not all of the world records are set with cut barrels, So accuracy and precision is a given, but what about durability.

For example,the Daniel Defense DDM4 has both versions available, but I hear conflicting reports on one barrel vs the other.

I own a cut barrel version and was wondering if I should buy another before the only version available is Hammer Forged. ( side note, Daniel Defense states that their chamber is also "hammer forged".

Any input ?

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Z-Michigan
May 16, 2010, 09:23 PM
Cut rifling is only found in custom aftermarket barrels, mostly for bolt-action precision rifles, and a tiny short list of OEM products (the only cut rifled OEM barrel I know of is on Armalite's AR-24 pistols; there are also the broach cut barrels on DSA SA-58 FAL rifles, but that's a slightly different process). The vast majority of commercial barrels are button rifled, not cut... and it makes a difference. Button rifling can still do a great job, but it's generally the cheapest fast process and fastest cheap process.

Your DD AR has a button rifled barrel, which is the standard for AR-15s.

Hammer forging is cheaper to make in LARGE production runs (e.g. Ruger, Remington, Glock) and produces a very good to wonderful barrel. In an AR-15 it provides some modest durability benefit, and accuracy is a toss-up, more a matter of quality of the individual barrel rather than the process used to rifle it. I would not buy a new rifle just to get a hammer forged barrel, but it is a nice to have feature if you were buying another rifle anyway.

Jim Watson
May 16, 2010, 11:14 PM
I don't think it matters until you are at the high end of benchrest or Long Range competition. Bear in mind that such highly regarded target and "precision" rifles as the Sako TRG series use hammer forged barrels.

Maverick223
May 16, 2010, 11:55 PM
IMO cut rifled barrels are the best for precision, specifically Krieger, but this comes at greater cost. Hammer forged have proved to be the most durable and long lasting, but generally gives up a bit of accuracy (not always the case). 99% of folks will do just fine with a standard button rifled barrel. For a standard production rifle, I worry far more about the company that built that barrel, and the overall build quality, than the method of manufacture for said barrel.

:)

Highcaliber
May 18, 2010, 12:13 AM
Thanks. I appreciate the feedback.

I've considered buying another Daniel Defense DDM4, because the cut barrel models are "on sale" for $1299 locally, originally $1599. But I may just go with the hammer forged version instead.

Z-Michigan
May 18, 2010, 12:21 AM
1) The standard barrels are not cut rifled, they're button rifled. I know I'm harping on this but it's a bigger difference than the magazine vs. "clip" terminology. Two completely different processes, typically used on different types of firearms and with different end results.

2) AIM Surplus has the basic M4 with the hammer forged barrel for $999 right now:
http://www.aimsurplus.com/product.aspx?item=F1DDXV&groupid=11
I don't think your local sale is a good sale!

Maverick223
May 18, 2010, 12:36 AM
From all accounts the CMMG Bargain Bin rifles are very good rifles (not much of an AR guy so my experience is limited), and are available at much less expense unless you are dead set on the DD carbine. Not sure of the type of barrel, but for $600.00 I wouldn't complain too much...heck you could take the extra cash and buy a Krieger (or whatever else strikes your fancy) to put on it if you like.

:)

Zak Smith
May 18, 2010, 01:12 AM
My 17" 3-Gun upper I had MSTN build for me in 2007 has a Krieger barrel. When new, it shot 1/3 MOA with Black Hills factory match ammo. Even now it still shoots 1 MOA. For a close-range training class, you can get by with a 3 MOA rifle -- for 3-Gun matches that have targets at 200-600 yards, a sub-moa AR can sure help.

For precision rifles, I always specify cut rifling with a 5R/5C profile. My experience with them on a variety of rifles and cartridges has been overwhelmingly positive.

PTK
May 18, 2010, 02:23 AM
I, too, prefer cut rifling to hammer-forged. I tend to only use the hammer forged stuff for semi-auto guns, single shot "toys", etc.

For my nice wildcat creation, I ended up paying extra for a cut rifled barrel, since I wanted a different twist rate, particular number of grooves, and so forth. They thought I was insane about the specifications, tried to tell me it was a bad choice, until I told them I would be firing .510" diameter 750-1000gr bullets at subsonic speeds. ;)

I tend to prefer Pac-Nor to Krieger, though I use both extensively. I stay away from Green Mountain (disliked their customer service) and unknown origin barrel blanks, for obvious reasons on both.

side note, Daniel Defense states that their chamber is also "hammer forged".

In the interest of safety, tolerance, etc., I sure hope not. :what:

Ol` Joe
May 18, 2010, 11:45 AM
Quote:
side note, Daniel Defense states that their chamber is also "hammer forged".
In the interest of safety, tolerance, etc., I sure hope not.

Why? More then a couple manufactures hammer forge their chambers along with the barrel. Here is an short artical on the various methods used.
http://www.rifleshootermag.com/gunsmithing/RSgunsmith1/

MachIVshooter
May 18, 2010, 12:03 PM
Where an M-4gery is concerned, 6 of one, half a dozen of the other.

For other applications, as touched on, there are advantages. Button rifling is pretty quick and very low cost equipment-wise compared to cut or hammer forged. Cut rifling equipment is less costly than hammer forging machines, but the process is very slow. Hammer forging has the highest equipment cost, but spits out tubes in less time than the other methods.

The reason cut rifling is preferred for accuracy is because the barrel is never stressed after initial forging. It is annealed, then may be hardened before or after drilling and cutting. Either way, the cutters do not stress the metal, and so it never is deformed and does not require being relieved after rifling as button-rifled or hammer forged barrels do.

For durability, hammer forged is hard to beat. They put a rifling die in the drilled tube and then beat the snot out of the outside until it conforms to the die on the inside. This makes the metal denser and tougher, but because of the elasticity of steel, there may be areas of the bore that are larger or smaller. This is why it is not usually the preferred type for accuracy, though there are (as noted) exceptions.

For keeping the cost of the firearm down while still offering good performance, button is fine. For this type, the barrel is drilled, and then the button, with it's wheels, is pushed or pulled down the bore, squishing the metal. This method does not produce the kind of diameter variations that hammer forging can, but because the metal is highly stressed from the process, it must still be relieved afterwards. That is when the dimensional variations will occur. The higher quality the forging and the more advanced the relieving/annealing/hardening process, the lower the likelihood of deformation. I have alot of button rifled guns that shoot very well.

Z-Michigan
May 18, 2010, 12:20 PM
Great post from MachIV.

A lot of additional info on hammer forging is available here:
http://technology.calumet.purdue.edu/met/higley/

As noted, many companies hammer forge the chamber as well, and that works just fine. Arguably it's better than cutting the chamber.

As also noted, button rifled barrels can shoot great. Savage, among others, uses them and Savages are known for excellent accuracy (for the price and compared to most other hunting rifles).

One issue with button rifling that can wreck accuracy is that the rifling rate of twist is not always the same throughout the bore, and if it slows towards the muzzle, accuracy is generally very poor.

benEzra
May 18, 2010, 01:06 PM
I suspect that whether or not the bore and chamber are chrome lined affects durability more than the method used to create the rifling.

If cut-rifled barrels are typically found on match-grade guns, then they might be less likely to be chrome plated, though.

Highcaliber
May 18, 2010, 06:34 PM
Thanks Z-Michigan but the rifle link you posted for $999 is NOT the same model.

I'm talking about the DDM4 in my OP, not the DDXV you posted. You listed the "base model" DDXV.

I'm talking about the DDM4 pictured here, with the Omega X 12.0 FSP rail system and MAGPUL MOE Buttstock & Mil-Spec 5 Position Receiver Extension, etc.
http://i46.photobucket.com/albums/f128/yeebyobb/DDM4.jpg

http://i46.photobucket.com/albums/f128/yeebyobb/DDXV.jpg

The model you mentioned from aimsurplus. has a standard Mil-Spec Buttstock and Mil-Spec Carbine Length Plastic Handguards.

So, actually the price here locally IS a good sale, on the DDM4 model, especially considering that the Omega X 12.0 FSP rail on the"DDM4" model lists for $346 to $356 on its own.

They're both fine examples.
Ordnance Grade 4150 MP Tested, Cold Hammer Forged, 1:7 Twist, Chrome Lined, M4 Profile, Bolt Carrier Group: Mil-Spec MP Tested, Properly Staked Gas Key, H Buffer, Mil-Spec Receiver Extension, etc.
The DDM4 also comes with a custom Daniel Defense Full-Latch 30ft Impact Plastic Case, and I don't think the DDXV does.

Here's the links for specs on both models.
DDM4 http://www.danieldefense.com/?page=shop/detail&product_id=141

DDXV http://www.danieldefense.com/?page=shop/detail&product_id=149

Highcaliber
May 18, 2010, 06:55 PM
I know we're talking AR15's here, not a surgical instrument for use beyond 1000+ yards, but I still can't decide.

Buy another "broach cut" version or the newer "hammer forged" version from Daniel Defenses' new barrel manufacturing facility.

I have a friend who regularly shoots 20" groups at 1000 yards with iron sights on his AR, and he has me leaning towards the "broach cut/Button rifled" version.

Thanks for all the opinions. and added info.

Button Rifled :uhoh: Hammer Forged

Hammer Forged :uhoh: Button Rifled

Maverick223
May 18, 2010, 07:23 PM
If you want to shoot 1k yds with an AR it would be best to choose a better long range cartridge (something like the 6.5Grendel), but if you are stuck on .223Rem/5.56NATO then make sure and get a 1:7 twist bbl to shoot the longer/heavier projectiles with a better BC.

:)

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