Since you asked Squid556
Simply put, the earlier rifles are now called “ slow” lock and have a knurled knob at the back of the bolt (like a 1903 Springfield), the design was improved, sear release sped up and the knurled knob eliminated around 1929 when the speed lock was introduced. The theory was less time between trigger actuation and actual firing means less chance for the shooter to move off point of aim. It seems to have worked since they became the premier smallbore target rifle for almost 50 years.
Slow lock
Speed lock
As far as what sets them apart, they were the most innovative rifle of their time. Totally new design for the initial rifle which evolved from a military style shooter for the returning doughboys when introduced in 1919, to a full blown dedicated benchrest heavy target rifle by the 30’s and for sure with the introduction of the B model with “Marksman” stock in the 40’s. They dominated that scene through the 60’s and into the 70’s. They really didn’t have a lot of real competition early on. Possibly Martini Henry action single shot rimfires or Remington rolling block targets in the 20’s ? Remington introduced the model 37 in 1937. Who would have thought! And improved it in 1940 to a much better rifle dedicated for target shooting. By the 60’s Anschutz came on to the scene and did very well. Especially the heavy 54 actions. All in all they stood the test of time from 1919 until production ceased in the mid 1970’s with the “E” designation rifles.
Simply put, the earlier rifles are now called “ slow” lock and have a knurled knob at the back of the bolt (like a 1903 Springfield), the design was improved, sear release sped up and the knurled knob eliminated around 1929 when the speed lock was introduced. The theory was less time between trigger actuation and actual firing means less chance for the shooter to move off point of aim. It seems to have worked since they became the premier smallbore target rifle for almost 50 years.
Slow lock
Speed lock
As far as what sets them apart, they were the most innovative rifle of their time. Totally new design for the initial rifle which evolved from a military style shooter for the returning doughboys when introduced in 1919, to a full blown dedicated benchrest heavy target rifle by the 30’s and for sure with the introduction of the B model with “Marksman” stock in the 40’s. They dominated that scene through the 60’s and into the 70’s. They really didn’t have a lot of real competition early on. Possibly Martini Henry action single shot rimfires or Remington rolling block targets in the 20’s ? Remington introduced the model 37 in 1937. Who would have thought! And improved it in 1940 to a much better rifle dedicated for target shooting. By the 60’s Anschutz came on to the scene and did very well. Especially the heavy 54 actions. All in all they stood the test of time from 1919 until production ceased in the mid 1970’s with the “E” designation rifles.
