lIt took me a little while to figure out what you are saying. My understanding is that you are going to sometimes load at home on your single stage and at other times go to your friends house and use his progressive press?

If I'm understanding you correctly, you are correct in that you will need the LnL bushing system to get your dies on your friends press. However that will be the extent of the convenience because you will still have to re-adjust your dies to his press and change them back when you go home to your single stage.

On my bench I have 3 presses, an RCBS single stage, an RCBS turret and a Hornady LnL Progressive. My most popular calibers are 9mm, 38 spl and 45 ACP. I like the idea of being able to load any of the 3 calibers either on the turret press or the progressive. I wanted my progressive to have an RCBS lock out die and separate bullet seating and crimp dies. I might add that on my turret press I also seat bullets and crimp with separate dies.

Soooo, this basically forced me to purchase separate die sets for each of my presses. I have in effect, 2 sets of 9mm, 38 spl and 45 acp dies. Depending on how your friend has his LnL set up you might also need to get a PTX for each caliber you load. The PTX puts the bell in the case mouth at the same time it drops the powder. This eliminates the expansion die allowing you to free up one of the 5 stations on the LnL. If you are using a lock out die (or powder cop) and seating/crimping with separate dies, you will need this ability.

Now, if you are still with me, I personally use RCBS and Lee dies on my RCBS Turret press and Dillon dies (with Hornady LnL bushings installed), an RCBS Lock out die (also with a LnL bushing installed) and the Hornady PTX on my LnL AP press. True it is a cost item but it saves me mucho headaches switching between presses. And my two presses are only two feet apart, not X amount of feet between your place and your friends place.

Much of what I'm saying may make no sense to you. Assuming that you are a beginner (I mean no offense), you have enough to learn without learning both a Single Stage and Progressive press at the same time. My advice is stick to your single stage until you have a complete understanding of what you are trying to accomplish before trying to comprehend the working of a progressive press. Granted, your friend should be a tremendous help. But switching dies between presses is probably going to be a major PITA. At least from my experience it is. For me, when I was beginning to handload, getting my dies and in particular my crimp dies properly adjusted was the hardest thing for me to comprehend.

Anyway I wish you the best of luck. While I chose Dillon dies because they are sold as 3 pc sets that exclude the expansion die and include separate bullet seat and crimp dies. You could accomplish the almost same result by using Lee 4 pc die sets at about half the cost of the Dillon. How you ask? Use the sizing die as intended, use the expansion die if you don't use the PTX, then use the combo bullet seating/crimp die to seat the bullet only and finally use the factory crimp die to put do the final crimp.

Again good luck. My prediction is that you will probably want to get your own LnL AP in short order so you can use the shell plates anyway.