Author Topic: Bullet pattern for the Gat  (Read 1701 times)

  • Guest
Bullet pattern for the Gat
« on: October 17, 2010, 07:07:00 PM »
I saw a video of a person firing a 22 caliber model Gatling Gun.  The pattern was all over the place (about 18\" variation at 35\' or so).  I do not know if this was a function of movement of the gun, or if if the variation was due to barrel missalignment.  I trust that it was more of the later.

Is this variation in spread related to inaccuricies in machining?

In the plans that I have (D&E), I do not see any provision for adjusting barrel alignment.  Am I missing something?  The plans have a sighting mechanism, but if the model I build is as far out as the unit I saw in action, I trust the bullets will be impacting outside the area delineated by the site.

  • Guest
Bullet pattern for the Gat
« Reply #1 on: October 17, 2010, 07:44:21 PM »
[quote name=\"gordonlynnbrown\"]I saw a video of a person firing a 22 caliber model Gatling Gun.  The pattern was all over the place (about 18\" variation at 35\' or so).  I do not know if this was a function of movement of the gun, or if if the variation was due to barrel missalignment.  I trust that it was more of the later.

Is this variation in spread related to inaccuricies in machining?

In the plans that I have (D&E), I do not see any provision for adjusting barrel alignment.  Am I missing something?  The plans have a sighting mechanism, but if the model I build is as far out as the unit I saw in action, I trust the bullets will be impacting outside the area delineated by the site.[/quote]

The original Gatling design was to produce a volley of shot (several models have cams that actively \'pan\' the gun side-to-side during cranking-- the RG plans have an \'oscillator\' option), so there\'s not typically any way to \'regulate\' the barrels beyond the BFH method.

  • Guest
Bullet pattern for the Gat
« Reply #2 on: January 17, 2011, 11:29:39 PM »
The original Gatling Guns may have been much more accurate than generally assumed. In fact viewing their intended use they were very capable of precision fire and on a par with the accuracy of the .45-70 Trapdoor Springfield Rifles issued to the troops firing the same ammunition. The following information is taken from the original Springfield Armory Inspection Manual for Caliber .45 Gatling Guns.

Quoted from  - \"Rules For The Inspection Of Gatling Guns, In Detail. National Armory Springfield, Ma\" circa 1875.

[size=150] Final Inspection[/size]

The gun being assembled, take hold of the crank and revolve the cylinder slowly, see that the working points do not bind, after which revolve rapidly. Observe that the front and rear barrel plates run true; also see that all parts are properly adjusted and fitted. Fire 100 shots.

[size=150]To Sight The Gun[/size]

Prepare a target, outer circle being 18 inches in diameter, with a two inch bull\'s eye five feet from the ground. Let the target be 200 yards removed from the gun. Fasten the gun carrage firmly to oak plank sunk in the ground, so that there can be no budge to the gun and carriage. Fire each barrel five or a less number of times, in order to establish the mean absolute deviation of centre of impact from the point aimed at. Corect its deviation in the following manner.

A steel band or brace having been fastened over the rear barrel plate to the frame, and a stand or support under the front barrel plate, the whole is held firmly in place. A socket wrench is now slipped over the muzzle of the barrel, which enables the latter to be sprung in a direction opposite to its deviation on the target, and the error is thereby corrected. Each barrel in turn is treated in the same manner, until the whole are adjusted. After this volley is fired, and in the event of there being no wind, the shots should all cluster within the 18 inch circle. In the preliminary firing the front sght has not been filed down, and the rear sight has been corredpondingly raised. The gun being left in the position in which it was aimed,the rear sight is brought down to its lowest point; the front sight is now filed down until its highest point is brought in line with the V of the rear sight and the bull\'s eye of the 200 yard target, and the sighting of the target is then complete; the graduations of the rear sight being constant for all guns of the same caliber.

Additional information from the Manual:


[size=150]To Adjust the Gun To Head Of Cartridge[/size]

Select a cartridge shell with the head of standard thickness. Place the shell in the carrier block,and turn it to position of firing. Remove the brass nut on front end of shaft, and with wrench on adjusting screw,  press back the axis on main shaft, until a slight friction on head of shell can be felt while passing firing point. Set up check nut and replace cap.

[size=150]Proof of Barrel [/size]

Fire each barrel twice with a charge of 200 grains of powder (service quality), and a ball weighting 920 grains. Use two wads for each charge, -one between the powder and ball, and the other over the ball. After proof, wash the barrel in hot soda water, and examine carefully for flaws, seams, or other defects. After satisfactory examination, stamp with proof letter P, \".4 from thread on surface near breech.

WOW, that is one heavy overcharge for a proof load, I wonder how many barrels did not pass.

This was taken from a reprint of:

Rules for the Inspection
[size=85]of [/size]
ARMY REVOLVERS
[size=85]and [/size]
GATLING GUNS

[size=85]PREPARED UNDER THE DIRECTION OF[/size]

LIEUT. COL, J. G. Benton
[size=85]Commanding National Armory,[/size]
[size=85]-By-[/size]
Capt. J. P. Farley, ORD. DEPT.

NATIONAL ARMORY
SPRINGFIELD, MASS.

This availaable as a reprint from Cornell Publications.

nitewatchman

  • Guest
Bullet pattern for the Gat
« Reply #3 on: January 20, 2011, 05:53:47 AM »
I would imagine that there is a lot of wobble of the gun created by the firer when they crank the handle. Don\'t know for definite as I\'m not finished on my D&E.