single stage presses

[Vassal]

Hey guys, I am frustrated with the ram movement in my RockChucker IV. It moves front to back (I am guestimating) 2+hundrreths at the top of the stroke. I don't have a concentricity guage (I need to fix that) so I can't test the work it does. I was looking to get a better press when I read a post here in "best single stage relaoding press" by German Salazar that seems to discount this problem. Even though the poster said his press acted as mine does most guys thought that wasn't the problem--or maybe they just wanted to talk about other issues with the guys set up. I don't know.
How can a press that has VERY noticable rame movement at the top of the stroke NOT be abig deal? Is the Forster really better? is the BigBoss more precise? Do I need to get a new press AND an Arbor/dies to load good ammo?
PLease those who have experienced NEW RCBS presses comment. They USED to be better (I guess) are the new ones just sloppy?

 

[fdshuster]

The new ones are being "made in China", so who knows? I've been using a Rockchucker that I bought new in 1991 & cannot detect any amount of slop in the ram that is a concern for me. I regularly check my loaded rounds for coincintricity using my Sinclair gauge, after using both the threaded (Redding) dies in the Rockchucker and after seating with my Arbor press (Sinclair). Any detectable runout problems I've had have been caused by an occassional piece of defective brass, not anything created by the dies or press. You have more ( a lot?) of a sloppy fit between the case head and the shellholder I would think. The case will self-center as it enters the sizing die I would think, and there would not be a problem unless the centerline of the die is radically off-center from the center-line of the ram. The shellholder slop would take care of any minor mis-alignement.

 

[LHSmith]

As Frank said above the case will self-center in the die. Actually Benchrest shooters have come up with modifications to presses to provide more "slop" so as to eliminate any bias that might be inherent in a factory press. One successful Texas BR shooter machines the ram on his Pardner press smaller in diameter , and some even machine the shell holder to provide more "slop. "

 

[Vassal]

This is exactly what I am trying to figure out. I looked very closely and it is definitely very near 2 hundreths movement. It comes straight forward so it seems to me like the rear of the shellholder tilts the case . during bullet seating it may just tilt inside the die and nose cone, affecting only slightly, but during sizing I can't imagine how this wouldn't push it off. I guess there is just no way for me to know without a concentricity guage. I got the Hornady about six months ago used it for a day or two and then realised that thing is actually pretty limited in what it can do. (Seems a generous statement even.) ITs gone.
I feel so powerless!!! It will be at least a month untill I can get a guage!!

 

[LHSmith]

Another, trick is to place an o-ring between the die lock nut and the press. How's your accuracy with your handloads? I and many pt. blank BR competitors never measure for concentricity on match loads. I use custom dies with unmodified Redding Boss presses and Wilson In-Line seaters. There are more influential things that I am more concerned with like condition reading, bench technique, and load tuning.

 

[Vassal]

OK I have spent some more time looking at this issue. I see now that the "slop" in the shellholder-case area IS enough to compensate for the tilt. The shellholder ram connection also has slop but this union is so flat that it would take alot of force to overcome the downward pressure; this is also true of the case-shellholder union though prehaps not as much because the case is not held tight to the rear. This seems to alleviate the issue just a little. The thing that saves this is the fact that although the downward force of the handle IS translated directly into forced movement (tilt) of the ram, it only does so if forced. MEaning I can gently find the stop and the case-die connection should be enough to hold it. This is probably true ONLY for dies with real pressure on the case. seaters will probably have enough unless soft seating bullets with little or no tension (like cast shooters do sometimes.) It seems like I can solve the problem by being especially gentle in finding the stop on the stroke. I have NOT been that way sometimes in the past; I didn't think it mattered,,, IT CLEARLY DOES!

Thanks VASSAL

 

[Vassal]

as far as accuracy,, well I do ok, I think. Its another issue, but I seem to shoot lights out with both my "accuracy" guns at 300, but move to four and five and the groups open up. I break an inch at 300 often but rarely break two at 400 or four at 500.. ??? With this issue out of my mind I may start with an arbor press for seating. Right now I am using stadard redding dies for both 223 and 6.5BPC.

I'll probably get some rubber for the rings also that may be the final tally toward a linkage with enough play to overcome any bump I may give finding the stop. I appreciate the help. This stuff is hard to learn, and I don't have money for experiments!! HEY send me a bossII AND another rock chucker,, lets try the forster, gimm'e an arbor press, make me some custom dies,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

 

[fdshuster]

Vassal: Moving out beyond 300 ( yards or meters) is where things start to get "interesting". Winds that you are not able to read & correct for, mirage in bright sun conditions, much more critical ballistics of the bullet, bench technique, etc. If group sizes are acceptable at 300 & closer, I don't see there being a problem created by the ram/press/shellholder/case fit. Get a good runout gauge when able, segregate the good, ( I consider .002" and less to be match quality), from the bad ( over .004" for me), and if you feel there is too much R/O, then start looking for fixes. I also tried the Hornady "Lock and Load" runout gauge when it first came on the market and was not impressed with it. The Sinclair has been my most reliable over the years.