A 300 meters run, especially deployed with OM3 MMF, should be an easy run for two J4858D so I believe you can expect 1Gbps Full Duplex without issues if optical cabling and patches is correctly deployed, tested and so certified. The 8360 32Y4C and 48Y6C models require configuration of "interface groups" only for ports 1-4 (as group #1) to enable the use of 10G transceivers / DACs in the SFP28 ports (Interface Groups default to 25G speed). Ports 1-4 on the 8360 32Y4C model do not support 1G transceivers. Specifically if you are using a 1GB MX (Multimode) SFP your distance is limited to 100m (330ft). You could be using the best quantum designed military grade fiber in the world and your distance limitation is still based on the timing characteristics of the MAC layer definition. The 2930F Switch Series models with 1G/10G SFP⁠+ ports added support for this J9054C/J9054D 100FX transceiver. The J9054C/J9054D are supported in models with 1G SFP ports.

This SFP fibre module is hot-swappable, making upgrades and replacements seamless by minimizing network disruptions. The J4858CST is an HP J4858C compatible fibre transceiver module that has been designed, programmed and tested to work with HP® brand switches and routers. It delivers dependable 1 GbE connectivity over fibre cable, for 1000BASE-SX compliant networks, with a maximum distance of up to 550 m (1804 ft). For use in the SFP ports on the models listed. Also for use in the dual-speed SFP⁠+ ports of the J9731A 2-Port 10GbE SFP⁠+ Module. Because they're using the entire width of the fiber, they "bounce" from "top to bottom" as you see in the picture. Modes traveling at the boundaries of the fiber travel faster, and modes traveling at the center travel a little bit slower. If you look at the picture where it says "Dispersion" you see that they don't quite arrive at the same time, this is a very very minute amount of time, however its enough to reduce bandwidth.Not supported for use in the following 3800 models: J9573A, J9574A, J9575A, and J9576A. The SFP⁠+ ports do not support 100M operation.

That's to say that using OM3 MMF or, better, OM4 MMF cables helps enhancing overall performance of optical signals and, probably, considering that, a valuable length can unofficially gained over the official 550 meters threshold value...but not so long (at some point shifting to SMF over MMF become a must if you have a long run) and nothing in that territory, in term of admissible official working values, should be taken for granted (somewhere - here as example - I saw reported a maximum distance of maybe 800/1000 meters, at best...and those values are not related to an Aruba SFP 1G SR Transceiver...indeed those values are not coming from something tested and declared by Aruba as per published standards...and indeed Aruba doesn't report those values too, see here a discussion about what is granted and what's not on MMF with SFP SR Aruba Transceivers). If you want to go to a longer distance you need to move to Single Mode Fiber and the matching SFP. Typically a SX or LX vs MX transceiver. R0X44C has the added feature of enabling the bottom ports to accept a 50G product, and in this mode, will NOT accept these 1G transceivers(see 50G SFP56 chapter). JL687A 32p 25G module requires configuration of "interface groups" (groups of 4 ports) to enable use of 1G or 10G transceivers or DACs in the SFP28 ports (default is to use 25G transceivers / DACs). See theThe 8325 requires configuration of "interface groups" (groups of 12 ports) to enable use of 1G or 10G transceivers or DACs in the SFP28 ports (Interface Groups default to 25G speed). See the Installation Guide for details.

The 8325 requires configuration of "interface groups" (groups of 12 ports) to enable use of 1G or 10G transceivers or DACs in the SFP28 ports (default is to use 25G transceivers / DACs). See the For use in the JL075A SFP⁠+ ports. Also used in an installed JL083A Aruba 3810M/2930M 4SFP⁠+ MACsec Module. For J9537A, J9549A, J9535A, and J9637A modules: K.15.02.0004 (for J9054B/C 1990-3613); K.15.08.0007 (for J9054C 1990-4112 and 1990-4483) J9054D: K.15.08.0007 For the J9308A module: K.14.34 (for J9054B/C 1990-3613); K.15.08.0007 (for J9054C 1990-4112 and 1990-4483) J9054D: K.15.08.0007 For J8705A and J8706A modules: All (for J9054B/C 1990-3613); K.15.08.0007 (for J9054C 1990-4112 and 1990-4483) J9054D: K.15.08.0007So first you need to understand that multimode fiber is named that way for a reason. There are multiple modes of light that are sent over the cable, so when light is transmitted it looks something like this: For use in the SFP ports of the 2530 Series Switches. (The J9853A, J9854A, J9855A, and J9856A models have 1G/10G SFP⁠+ ports that do not support these 100Mbps transceiver modules.) For J9451A: K.14.24 (for J9054B/C 1990-3613); K.15.08.0007 (for J9054C 1990-4112 and 1990-4483) J9054D: K.15.08.0007