I found this in the pro38.com faqs:
What’s the deal with cross-brand compatibility?
Pro75® and Pro98® reloads kits fit both our own hardware, and RMS™ systems. The only difference is the type and number of o-rings used. All ProX™ cross-brand compatible reloads are supplied with the o-rings required for each type of hardware.
History:
While CTI had planned all along to develop 75mm and 98mm products in the ProXX line, originally we had not planned to make them cross brand compatible but instead wanted to incorporate some fresh approaches as we did with the smaller sizes.
Before we had started any real work on the 75mm and 98mm products, a commercial customer asked us if we would develop some high thrust M class 98mm reloads that would fit their inventory of RMS™ 98/10240 hardware. Their test program was in serious jeopardy as the supply of reloads had dried up due to the disaster at Aerotech's plant. We said sure, no problem, and began work developing a custom reload for their application, the M3800. The only component that was not readily available was the nozzle; so we manufactured a mold for compatible nozzles. CTI already had in-house mold making and compression molding equipment so this was no big deal. The time from receipt of order to the first test firings was no more than about two months - our customer was in a hurry! The M3800 worked perfectly in their tests, and more were subsequently ordered. This quick-turnaround work led to a production contract for larger booster motors.
Once word spread through the rumor mill that we had made the M3800's, we got frantic requests from our Canadian dealers and customers for RMS™-compatible reloads as their large motor HPR activity had nearly ground to a halt due to lack of supply. So we also made a compatible single-throat nozzle mold for 75mm reloads and brought in a supply of liners, inhibitor etc. Several prototype 75mm and 98mm motors were flown at the ROC Lake launch in June 2002, all in RMS® hardware.
After that it quickly became apparent that there was great interest in and a need for 75 and 98mm reloads to fit flier's existing hardware. People told us they wanted alternatives, and the concept began to make more and more sense especially in light of the high cost of large hardware. Therefore we forged ahead with development of a complete line of reloads for the sport rocket market. We also designed our own hardware, incorporating our own ideas for improvement wherever possible while maintaining compatibility.
The concept of alternate brand (non-OEM) consumables or repair parts is nothing new in the world of commerce - this goes on in a vast array of industries; copiers, printers, automobile parts, ammunition to name just a handful. It therefore is somewhat inevitable that it would surface in the sport rocket market at some time. We just did it first!
Certification status
Cross brand compatible reloads are new to HPR/MR, therefore none of the rules and regulations of the rocketry associations addressed the situation adequately when first introduced. After some discussion between the HPR associations' motor testing committees, it was decided that cross brand compatible reloads had to undergo a complete certification firing series in any hardware in which they were to be offered for use.
Currently the following reloads are certified for use in CTI ProX™ hardware and RMS™ hardware:
Pro75®
Classic™ propellant reloads: K510-P, L800-P, L1115-P, and M1400-P.
White Thunder™ propellant reloads: K1085-P, L1720-P and L2375-P
Red Lightning™ propellant reloads: M1810-P
Blue Streak™ propellant reloads: M1670-P
Skidmark™ propellant reloads: M1770-P
Pro98®
Classic™ propellant reloads: L600-P, M1060-P, M1495-P, and N2500-P.
White Thunder™ propellant reloads: M2505-P
Red Lightning™ propellant reloads: M1890-P
Vmax™ propellant reloads: L3150-P
Classic™ propellant moonburners: M520-P, M795-P, N1100-P.
Skidmark™ propellant reloads: 8088M1790-P
How about the other way around - can RMS™ 75mm or 98mm reloads be fired in CTI hardware?
Currently no RMS™ reloads are certified for use in CTI ProX™ hardware. It is up to the reload manufacturer to supply reloads and hardware to the motor testing committees for certification firing. If Aerotech chooses to have their reloads certified for use in ProX™ hardware, that's fine but it's up to them to do so - you'll have to contact them with any questions on that subject.
Functionally, however, the answer is yes. Compatibility works both ways. We have compatible hardware in all equivalent 75mm sizes and 98mm sizes from 98/5120 up to 98/15360 case size. Several RMS™ reloads have already been flown in ProX™ hardware at Canadian launches. The only thing extra that is needed is a set of the correct o-rings for the ProX™ hardware.
Cross reference as to which RMS™ case is to be used with which CTI™ reload
Pro75-2G = RMS75/2560
Pro75-3G = RMS75/3840
Pro75-4G = RMS75/5120
Pro75-5G = RMS75/6400
Pro75-6G = RMS75/7680
Pro98-1G = RMS98/2560
Pro98-2G = RMS98/5120
Pro98-3G = RMS98/7680
Pro98-4G = RMS98/10240
Pro98-6G = RMS98/15360
What about the Pro-X™ No hassle warranty with cross compatible hardware?
In the event of a warranty claim where a ProX™ grain is used in a compatible motor case, we replace (on a case by case basis) the hardware with our ProX™ brand hardware, not a monetary refund or a case from the original manufacturer. The ProX™ line now has a large selection of Pro75 reloads, and a replacement case from ProX™ will not limit the flyer in terms of available colors and/or effects in any way. Further, ProX™ hardware will support an even wider variety of options in the (near) future.
I guess the challenge is getting the right o-rings...???
