A STUDY OF SOME FACTORS INFLUENCING THE BOLT LIFT OF THE SPRINGFIELD RIFLE
Abstract
The bolt lift required to extract the cartridge case from the chamber of the Springfield was measured under various conditions in an effort to find ways of improving the extraction characteristics of the semi-automatic rifle under conditions of firing in a hot gun. Cartridges were soaked in the chamber for periods up to 4 minutes before being fired in a rifle heated by rapid fire. Bolt lift was found to be maximum for rounds fired immediately upon being chambered in a hot gun; it was somewhat lower for rounds soaked 4 minutes before being fired, but it was still much higher than for rounds fired in a cold gun or for rounds fired after being heated about a minute in a hot gun. Comparative tests were made using a worn gun and a relatively new one which showed that bolt lift tended to be lower in the worn one. An effort was made to measure the effect of clearance in the chamber on the bolt lift in a hot gun by firing minimum cartridges selected with an improvised gauge, but the results were inconclusive. Two modified bolts had no appreciable effect on the bolt lift. Piezo-electric gauge records were taken of rounds heated in an oven which showed that the high pressures developed by hot rounds are due to more rapid combustion of the charge in the normal way.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 10, 1936
- Accession Number
- AD0701178
Entities
People
- L. A. Carten
Organizations
- Ballistic Research Laboratory