I have a 4506-1 that I want to convert to 45 Super. My understanding is that I will need to use a 20 pound spring. But as I bought this pistol used, I don’t know what spring is in it. The fund shoots 45 standard velocity without a problem. How can I measure the “poundage” of the spring now in the pistol?

According to Wolf Gunsprings, the factory recoil spring rating for a 4506 is 14#. Check out this page: https://www.gunsprings.com/SMI...ID1/mID58/dID261#876
(You will have to scroll down a bit for the 4506.)

My concern is that, since I bought the pistol used, the previous owner may have put in a heavier spring. So I may not have the factory spring in the pistol. It does take more effort to pull the slide back than on any other gun I own.

A new spring from Brownells is pretty inexpensive, then you know where you are.

I don't know of any way without specialized equipment. You need to have a scale, know at what length the spring is compressed to for measurement, and hold the long skinny spring without kinking or having it fly away altogether.

Since the spring in there works fine with standard ammunition

And you want a 20# spring for the 45SUPER

Just but a 20# spring and don't worry what the other one is

BTW, I am a HUGE 45SUPER fan myself

I have been hand loading and shooting the 45SUPER since it's introduction in the late 1980s

If you are going to place an order anyway, since they are cheap, I would get a replacement factory weight spring along with the #20 and toss what is in there now since you don't know the weight or how old and worn it may be.

if you want to measure it you will have to build or buy a fixture. The costs and time of that are so much more than just buying a spring it would be nuts to do so.

What you’re referring to is known as spring rate. It’s defined as the mass required (in this case, measured in pounds) to compress the spring one inch.

You’d have to build an adjustable device to hold the various diameters and lengths of recoil springs, have access to a bunch of different precise weights to set on top of the springs, and a way to accurately measure exactly one inch of compression.

I have several spring rate testers for big racing stuff like coil suspension springs. If you do a quick search on spring rate testers you will see a bunch of ideas for design. But these small springs I would just make a simple base with a rod that the spring can go over (like the equivalent of a recoil rod) mount the spring, make a weight with a known relevant poundage to the rate that you want and a hole in the centerto also go over the rod and then measure the deflection with a dial caliper.
It wouldn't be very hard to do. But when the springs are a few dollars each it seems counterintuitive to go to that effort given the springs are readily available.

quote:

Originally posted by striker1:
What you’re referring to is known as spring rate. It’s defined as the mass required (in this case, measured in pounds) to compress the spring one inch.

It's actually the force required to compress, not mass. Pounds are a measure of force, not mass. In the English system, mass is measured in slugs, but since almost all measures of mass assumed constant gravity, pounds of force exerted by a given mass at earth's gravity are used to express a proxy for mass.

In metric it is more sensible where grams are a standard measure of mass and newtons are the measure of force, and masses are expressed in the mass, but still generally measured by the force they exert at constant gravity (weighing).

You guys mean you don't just put the spring on the bathroom scale to measure 14 pounds, or 20 pounds? I have been doing it all wrong.

Rack slide & ease it forward until it is slightly out of battery. Release slide & it should kick into battery. If not change spring.

quote:

Originally posted by DNS:
Rack slide & ease it forward until it is slightly out of battery. Release slide & it should kick into battery. If not change spring.

This isn't remotely the answer to the question asked.

I have seen fixtures for testing recoil springs as described above. They look like a modified trigger gauge. They likely aren't expensive, but a new spring is likely much cheaper. If you are concerned with longevity, buy several and pick a replacement interval.

Here are instructions to make a cheap gauge:

https://forums.brianenos.com/t...ecoil-spring-tester/