7mm RM vs 300WM

[.44]

What is the interchangeability of components regarding both these calibers. For example, 300WM bullets can be used to load .308 which makes it cheaper for me to feed my ARs and a WM rifle. Not familiar with the 7mm cartridge. Both are flat-shooting cartridges.

[RNE228]

Which 7mm? 7mm-08, 7mm Rem Mag, 7x57 Mauser, 284 Win to name a few ... there are a number of 7mm caliber cartridges.

Best option is to browse thru a reloading book.

https://www.accurateshooter.com/featured/7mm/

https://www.grandviewoutdoors.com/gear/hunting/top-10-7mm-hunting-cartridges-time

https://www.chuckhawks.com/7mm_musings.htm

[NapalmCheese]

I'm not entirely certain what you're trying to get at but...

TL;DR - you can share components but it doesn't always make sense. Sharing components between magnum class 7mm's makes sense, but trying to share components between magnum class, .308 class, and PPC class cases isn't worth it.

Nearly any 7mm chambering can use a wide variety of 7mm bullets. Common bullet weights for 7 RM overlap well with 7 WSM, 7 LRM, and 7 STW (among others) and somewhat but not entirely with common bullet weights for 7mm-08, 7 TCU and 7x57. All (or most) of those cartridges use the same primer, some share powders with varying degrees of success.

What do you have (or want to get) and what are you trying to do?

Por ejemplo, 168 grain Berger VLDs can be used in 7mm-08, but 7mm-08 doesn't have the case capacity to make them all that useful for hunting. 7 RM (and similar cartridges) do better with that bullet. Likewise with the 145 LRX from Barnes. The 139 LRX can be very effective in 7mm-08 AND 7 RM, but the 145 is a better choice for the 7 RM since that 6 grains of weight gets you a better ballistic coefficient and makes little difference in velocity from the larger magnum sized cases; but it makes a LOT of difference in smaller .308 sized cases. Meanwhile something like 7 TCU shouldn't be used with big 7mm bullets at all, but a 110 grain TTSX works well in both 7 TCU and 7mm-08. That same bullet is of limited use in something like 7 RM, 7 LRM, and 7 STW which will push it lightning fast but because of it's poor ballistic coefficient wouldn't net you much gain in terminal effectiveness on game heavier bullet (120 or 140 grain) fired slightly more slowly.

As another example: in 7mm-08 I can get a 145 LRX moving about 2650 FPS with a 22 inch barrel. I can get a 110 TTSX moving about 3175 with that same barrel. From 0-200 yards (give or take) the 110 TTSX will impact with greater than 2600 FPS and is the better killer. From 200-500 yards it's pretty much a wash, though the 145 LRX having more mass will likely have better penetration (not that the 110 TTSX lacks that). At 500 yards the 110 TTSX is around 2000 FPS and I no longer trust it to reliably expand, the LRX should expand out to 700 yards; so for shooting game from 500-700 yards the LRX wins. As such there's pretty much no reason to ever load the 146 LRX in 7mm-08 for killing game.

Both of those bullets can be used in 7 STW, but 7 STW can start the 145 LRX at 3200 fps (starting the 110 at 3600 fps). So when you run the numbers both the 145 LRX and the 110 TTSX cross 2600 fps impact velocities at around 400 yards and the 145 LRX is the better bullet pas that distance; so there is no point in using the 110 TTSX in something like 7 STW.

If you compare max point blank range (+/- 3 inches) of the 110 TTSX to the 145 LRX in 7 STW, you have an MPBR of 357 yards vs 336 yards (21 yard difference). In 7mm-08 your MPBR is 319 vs. 281 (38 yard difference). Which again makes it seem like there's no reason to use something like the 110 TTSX in 7 STW, and no reason to use the 145 LRX in 7mm-08. So even though you CAN share bullets between the two, you're not REALLY going to share bullets between the two.

Same with powders.