IMR Classic
IMR 4320
A general-purpose medium-speed rifle powder that served mid-capacity varmint and standard hunting cartridges before it was dropped.
Discontinued. It sat between IMR 4064 and IMR 4350 as a general-purpose medium rifle powder for .30-06, .308 and the fast .22 centerfires, and it never developed a following distinct from the powders on either side of it, which is roughly why it was dropped. If you have some it is a perfectly good .30-06 powder; there is no reason to go hunting for more.
- .30-06 general purpose
- .308 Winchester
- .22-250 Remington
Who has IMR 4320 today
Checked October 10Out of stock at every store we track
| Store | Size | Shelf | In hand /lb | Stock |
|---|---|---|---|---|
| Lohman ArmsHazmat charged, amount not published | 8 lb | $299.99 | $41.43 est. | Out |
| Lohman ArmsHazmat charged, amount not published | 1 lb | $36.99 | $68.43 est. | Out |
“In hand” is the shelf price plus that store’s hazmat fee and shipping, spread over one container. Stock is checked once a day — confirm on the store’s page before ordering. Compare all powders →
Discontinued. Canisters still circulate, but the maker no longer produces it — and load data for it may be withdrawn or archived.
Specifications
| Manufacturer | IMR |
|---|---|
| Product family | IMR Classic |
| Status | Discontinued |
| Application | rifle |
| Grain form | extruded |
| Lee VMD (bulk density) | 0.0716 cc per grain · 0.91 g/cc |
| Composition | single-base |
| Typical cartridges | 308 Winchester, 30-06 Springfield, 22-250 Remington, 220 Swift |
Grain shape
Extruded single-perforated sticks, neutral-burning, with the same handling behavior as the rest of the classic IMR medium range: long kernels bridge and shear in a measure, so weigh rather than throw.
Why geometry decides burn rate more than chemistry does: Shape Is the Product.
Discontinued. Hodgdon no longer lists this powder among current IMR products and it does not appear on Hodgdon's current relative burn rate chart. Historical published data for it may still appear in older Hodgdon and IMR manuals; check the current Reloading Data Center before assuming coverage.
This powder is obscure enough in the US that its practical character is thinly documented. The note above is deliberately short rather than padded.
Data confidence
We flag entries we could not fully verify rather than presenting them as solid:
- Discontinued — no live manufacturer product page; details drawn from archived or secondary manufacturer material.
Sources
The specifications above come from IMR's own published documentation, linked below. The two “RCM's read” sections are ours, not theirs — our assessment of what this powder is like to load, drawn from its published characteristics and from what handloaders consistently report. No manufacturer endorses them and no source below backs them. If you think we have one wrong, tell us — we would rather fix it.