RCBS hand held APS primer tool.

Modifying springs on moving parts can effect timing and function. Cutting the spring could make it too short. Sanding springs can cut the pressure but if you cut too much pressure it might not allow it to work properly.

There are several companies that make "standard" small extension or compression springs. Do a search on the internet. there are also several that will make springs to order but you probably do not want to pay for the minimum quantity.

Anyway, most of the small springs are specified by the number of coils, the diameter of the wire, and the ends on the springs. These companies may have a spring that is the same general size as the RCBS spring but with wire size or number of coils changes to go the spring rate direction that you want.

As an alternate, i would get a replacement spring from RCBS before modifying it. Makes it easy to return to original if your modifications do not work.

I use an RCBS Universal APS hand primer on occasions and it works just fine for me. I have never had it apart so I do not know how it is laid out inside.

Hope this helps.

I'm at a loss to understand why you'd want to make the handle spring 1/3 to 1/2 less strong. I have small hands and I don't have any problem with fatigue pressing the handle. Nevertheless, to get to the interior spring you have to remove the handle via the spring clips holding the handle in. I haven't taken it apart that far, so I don't know what all is going to fall out the bottom....I assume the spring you are referring to will. Then you can see what size it is.

As for the other spring "hanging out" as you described, that spring does nothing until the black linkage connected to the end of the handle (which slides over the spring) reaches the ball at the end of said spring....the continuing the squeeze at that point, stretches said spring, which pulls the strip into the next primer position. I don't think that operation in any way is connected, timing wise, to the internal spring....therefore "halving" the strength of the internal spring probably won't effect that operation unless it's no longer strong enough to return the handle on its own to the starting position. That would be the worry....only a test would tell. Shortening the internal spring would probably induce unsprung play in the handle, so only a weaker (smaller diameter wire) spring of the same length would be a possible choice. Good luck with your experiment.

My Picture Review of the APS Hand Primer was posted on AR15.com

Included it here to show people what we are talking about.

If the strip indexes too far, I would suspect one of the two black plastic "U"'s (like the one shown laying on the tool in the picture below) has a leg snapped off. Mine doesn't do that.

It's easy to break one if you happen to try to pull it out the wrong way.

If that's the problem, a call to RCBS will get some coming your way .... free of course.

Call RCBS. They'll tell you how to fix it, send parts, or they may just send you a new one.

stubbicatt said:

Wow Thanks GW Starr. I am looking at your photo, and I am not sure what part you are referring to, but is it that part laying atop the tool, not down in the trough?

With mine, when the APS strip indexes, it *just* squeeks the next primer past top dead center, unless as I release the handle, if near the end of its stroke, I very gently and slowly release it, all is well. If I release it anything less precisely, then I have to gently tug the APS strip backwards, maybe the distance of 1/2 primer radius, to get things to line up.

Click to expand...

Yes, the part that appears to be laying atop the tool. (it is actually indented a 32nd or so and is called a Detent) There should be one of those little black plastic Detents on each side, but the picture shows only one. Too much light in the picture...so where the part sits is not so clear....but it is where it goes. Notice what would happen if the strip is pulled backwards....that arm (and perhaps the other one on the opposite side of the strip as well) may be snapped off. They act as stops. Flexible one way...not the other.

Also notice the black plastic trough (called the pusher) that has 2 raised one-way stops on each vertical side. The strips slide through that one-way. If you really yank backwards you can break one or more of those raised stops as well. So the "pusher" pushes the strip and the detent stops the strip at the right place. Hope that helps.

stubbicatt said:

What I received is the part that fits between the squeeze handle and the bottom of the plunger, ........

I find that it indexes only with the APS strip going in one way, with the "open" end of the strip first.
GWStaar, I took the top off my primer tool, and I was unable to find anything that looked like that U shaped thing in there anywhere. It is clear to me that these are the missing parts that are hinking up my indexing. I will call RCBS on Monday and request these parts.

Click to expand...

Well that was certainly the wrong part.

Indexing going in one way with open end first is correct. Trying to go any other way will break the parts I'm talking about.


The "u" shaped part (need 2) is part #186265 (key #6) in an exploded view of the Pro 2000 auto-advance press. That exploded view is found on RCBS's site. Go to this RCBS page ....click the first listing under presses....go to page 13. (They aren't furnishing the manual for your tool on the web yet so that is the 2nd best thing because they are the same parts unless of course the design has recently changed which I know nothing about).

The other part critical to strip advance (need 1) is part #186264 APS HPT STRIP PUSHER (key#5 on the exploded parts picture.) But if the strips are pushing, that part is probably okay. The detents stop it where it's suppose to stop.