Springfield Armory Model 1888 made into Positive Cam Rifle

Serial Number 415109

.45/70

 

This rifle has been determined to not be a completely original Positive Cam Rifle.  As stated below it appears that a standard receiver with a close serial number was re-machined and re-blued.  It was mated up with an original and proper Positive Cam breech block assembly and stock.

Springfield Armory received field reports of instances when trapdoor Springfield breech blocks stuck shut or blew open when the rifle discharged while loading.  The first examination of the problems was a result of Springfield Armory Post Order No. 17, dated April 19, 1883.  Lieutenant Colonel A. R. Buffington set up a board of three officers and the Master Armorer to investigate.  No recommendations were made at that time.  On November 5, 1886, another board with Colonel Buffington was set up and the result was “Board did not feel justified in recommending such changes until the insecurity or other possible defects of the present mechanism become more evident”.  The results of Colonel Buffington’s recommendation resulted in no locking cam systems being made at that time. 

The issue of the breech block sticking in the closed position was attributed to the expansion of the breech parts when heated up during rapid fire.  The locking cam breech was the result of the research into the problem.  The theory was that by lifting the thumb piece the stuck cam would be moved left off of its seat freeing up the breech block so it could be opened.  This feature also made the lock up of the breech stronger and capable of higher pressures.  The system was used in the experimental trapdoors during the development of the smokeless .30 caliber round (.30/40) that would be used in the Krag rifle in 1892.

The issue of the rifle discharging while loading was attributed to either a firing pin stuck in the forward position or a broken firing pin with the tip stuck in the breach face.  There was experimentation with different alloys to make the firing pins more durable and less prone to corrosion.  An alloy of aluminum, copper and tin proved to be more durable and was approved for use in December of 1886.  Springfield referred to the alloy as aluminum bronze.

Positive cam rifles were developed experimentally and about 100 were produced during the fiscal year of 1888.  Most serial numbers are in the 415,000 range and are mostly sequential.  Some sources think the serial numbers ranged from 415502 to 415615 consecutively with the exception of a few rejects during production.  This rifles receiver was produced between July and September of 1888.  There are records stating that the rifles were sent to San Antonio Arsenal for testing.  Some sources believe they were not tested while other sources believe they were tested and saw service in Texas, New Mexico and Arizona.

These rifles are identical to the Model 1884 except for the receiver, breech screw, breech block, firing pin and screw, and cam latch components.  The shaft of the cam latches has coarse thread which fit a like female thread cut into the breech block cap.  The receivers are recessed on the right rear inside to accept the breech block caps shoulders that are larger than on standard caps.  When viewing the breech block from the rear, lifting the thumb latch will move the cam to the left, freeing it from its positive locking position, and lowering the thumb latch will move the cam to the right to its locked position.  The firing pin retaining screw hole is on the right side of the breech block instead of the bottom.

This rifle has a documented sales history going back to 1999. A listing for this rifle in catalog number 146 of “Guns of the West” by Gary Hendershott on page 11 for $9,550 in 1999.  He listed it again in 2012 on page 12 in an unnumbered catalog with a price of $7,500.  It was sold by Cowan’s Auctions on May 1, 2013 for $4,025.  The previous owner purchased it from Collectors Firearms in Huston, Texas for $5,785. 

The breech block of this rifle is a correct positive cam and marked U.S. over MODEL over 1888. It does have a proper aluminum bronze firing pin.  The pin is retained with a screw on the right side of the breech block behind the thumb piece of the cam latch.  The firing pins retaining screw notch is cut on the bottom of the pin at an angle and is not perpendicular to the shaft because of the compound angle that the pin as it passes through the breech block.  The cam shaft has a bright, in the white, finish where the thumb piece is blued.  The thumb piece is secured with a screw mentioned above.

The 100 rifles produced are the only ones that Springfield made having the 1888 date on the breech blocks. 

The inspector’s cartouche of Samuel W. Porter, SWP over 1888, is in a box on the left wrist of the stock.  The firing proof script P in a circle is rear of the trigger plate.  The stock is in very good condition with moderate nicks, dings and scratches.

The relief cut in the right rear of the receiver for the breech block cap has the same finish as the rest of the receiver and barrel.  If it was cut into an earlier receiver outside the excepted serial number range the whole receiver was refinished over the pitting.  A close comparison with an original receiver shows that the relief cut is slightly different.

The barrel proof and inspection marks are on the left rear of the barrel.  The V and P are 0.130” high.  From the top of the V to the bottom of the eagle head is 0.560”.  Head space checks perfect and is close to the no go dimension.  The bore is in very good condition with only a few spots of shallow pitting.  All metal surfaces are better than 95% original blued finish or case colors.  

The lock plate has the eagle motif and U.S. over SPRINGFIELD.  The eagles shield is 0.20” high and 0.150” wide.  The eagle is 0.476” high with a wing span of 0.675”.  The word SPRINGFIELD is 1.1” long and 0.10” high.  This lock plate was used from about serial number 380,000 to 490,000.  The tumbler has three notches.

The sights on this rifle are of the last variant used on the trapdoors.  The rear is a Buffington with 0.380” diameter knobs and the front is the pinned in replaceable with a rounded rear edge and thinned sides.

Published dimensions                                                 This rifle

O.A.L.                                     52”                              52”

Stock length                            48 3/4”                        48 13/16”                   

Barrel length                           32.6”                           32 5/8”

Muzzle diameter                     0.73”                           0.73”

Front sight length                    5/16”                           5/16”

Sight from muzzle                   1 1/4”                          1 1/4”

Ramrod length                        35.6”                           35 9/16”

Rod cannelures                        3 1/8”                          3 1/8”

Head space      Go = .070”   No Go = .075”               .078”

Various other markings

Butt plate                                US

Barrel bands                            U

Inside belly of stock               U

Stock rear of trigger plate       Y

Butt plate back                        1

Trigger plate                           V, D

Trigger                                                 S

Sear                                         Z

Sear spring                              O

Tumbler                                   7

Main spring base end              3

Main spring hook end             W

Top rear of barrel                    A

Left rear of barrel                    R

Bottom of barrel                      B, P and tilde

Breech screw                           B

Bottom of receiver                  X, T and possible U