How important is it to trim a Douglas barrel?

[Dphariss]

This is not a description for the Douglas ML barrels. Cut at the muzzle 1.5-2”. Is shortening it more than this cut off at the breech and rethread for the breech to keep the bore centered at the muzzle.

Here's GRDouglas's info on their bbls from some years ago.
Note the statement at the bottom regarding cutting the muzzle end off.

A brief description of our barrels.

BASIC BARREL
This is a rifled bar of steel, cylindrical in shape, with a rough lathe turned finish. These barrels will vary in diameter but will always finish at least 1.200" O.D. This barrel is available in three lengths as noted on the price list and barrel shape chart. This blank is intended for those gunsmiths who wish to turn and shape their own barrels.

THE PRETURNED BARREL
This barrel is rough turned to approx. size and shape. Usually it will be .025" to .050" larger than the finished dimensions noted on the barrel size chart. It will be finish centered and will have a rough lathe finish. It is intended to be finish centered and final shaped by you. It comes to you 1-1/2" longer than chart dimension.

THE FINISHED TURNED BARREL
The finished turned barrel is to approx. chart dimensions within a few thousandths. It will have been finish centered accurately on a lathe and turned to dimension and then belt sanded with the final grit size being 180. It also comes to you 1-1/2" over length.

THE FINISHED, THREADED AND CHAMBERED BARREL
Here we use the finish turned barrel above and then cut the proper thread for the action involved, chamber for the cartridge ordered and crown the barrel. The chamber in this barrel is finished in the sense that a finishing reamer is not required. You must however make a slight cut on the breech with a lathe and have a method of gaging headspace. DO NOT FIRE this barrel without making this adjustment. A set of instructions will be enclosed in the package. Be sure that you do not throw it away with the wrapping material.

GRADES OF BARRELS AVAILABLE
Standard grade is a barrel that meets our dimension specifications but may have a minor amount of curvature. Truly, however, I see barrels in our scrap that are straighter than most factory barrels. A PREMIUM grade barrel is one that has been judged straight in checking. It will be marked with the symbol XX to designate this.

AIR GAGED QUALITY
In the process of checking our barrels all are checked with air gaging equipment. In so doing we find some that are more uniform than others. Those that measure .0001" or less variation from one end to the other are classed as air gaged. This does not mean that should you order a barrel of a lower quality grade that you might not receive a barrel that would have graded AIR GAGE but it does mean that if you specify AIR GAGE you will get a barrel with the tolerance indicated above.
You will find that most of our basic barrels are marked for the muzzle end. In the process of air gaging we mark the tight end as being the muzzle. Some people feel that the taper should be to the muzzle, others say that it makes no difference. At any rate the barrel is marked so the choice is yours.

PISTOL BARRELS
Many handgun shooters are having great success with DOUGLAS barrels. We do NOT install these barrels. We do supply basic blanks in chrome moly only, to pistolsmiths and gunsmiths who do cut and fit these blanks to handguns. We do no pistolsmithing with the exception of some silhouette barrels (See below).

SILHOUETTE BARRELS FOR HANDGUNS
Silhouette shooting with handguns is becoming very popular. Most barrel makers are supplying a single shape for this pur pose. We have been supplying our regular sporter shapes and the customers have been cutting to 15" or whatever the customer desires. This allows a choice of weights so as to match stock, action and sights to weight limits. We will fit barrels and supply FTC barrels in suitable calibers for the Remington XP100 action only. Price is the same as for a rifle barrel.

SILHOUETTE and super magnum shape - This barrel shape was developed for silhouette shooting and high pressure 45 caliber cartridges. In the silhouette adaptation the breech diameter is always 1.200" muzzle diameter 750" and an O.A.L. of 24" to meet the weight requirements of this sport. The barrel used with the 458 cartridges will have an appropriate diameter for the action involved. This barrel is available in lengths from 22" thru 26". All these barrels have our sporter profile. Weight of the silhouette barrel is approx. 4 lbs. 7 ½ oz.

NOTE: You must cut 1 ½ “ off of the muzzle of all BASIC, PRET and FT barrels.


Why?,,I don't know.
It's just what the mfg'r of the bbl sez to do.
Plus they send(sent?) you those 3 types of bbls 1 1/2" longer than the cataloged/ordered length just so you could cut them down that amt.

Must be something to it or it would seem they wouldn't have bothered to waste the time, matr'l and writing about it.

[kutter]

No, it's not a statement aimed specifically at M/L bbl's. Maybe printed after they stopped making them.
I have no idea..
But the same principles would apply would they not if the bbls, no matter if made for a M/L or a cartridge gun, were mfg'd in the same way.

Something to do with the cutter/button as it exits  the muzzle during the process that they seemed concerned enough about accuracy or spec to mention elliminating a couple inches from that end.
Is that such a big deal. The bbls were supplied with the extra length to be lopped off to you would end up with the standard length.

They said it, they made the bbls,, but you can do what ever you want to of course.

Big deal over nothing.

[whetrock]

I appreciate you taking time to post the information, Kutter.
Thanks.