Lyman MSR Ammo Checker Block Multi-Caliber Aluminum Black

The Lyman MSR Ammo Checker Block is a precision reloading accessory machined from a solid block of 6061 T6 aircraft-grade aluminum and cut with custom tooling to SAAMI minimum chamber dimensions. The black anodized block lets the reloader confirm that handloaded ammunition will drop freely into a spec chamber before it ever goes near a live rifle. This is the single most important safety check you can perform on a finished round.

This multi-caliber gauge (Lyman part number 7833003) covers the most popular modern sporting rifle cartridges in a single block, including .223 Rem/5.56x45mm NATO, 6.5 Grendel, 6.8 Rem. SPC, 7.62x39mm, .300 Blackout, .450 Bushmaster, .458 SOCOM, and .50 Beowulf. Each chamber is cut to the tightest SAAMI spec for that cartridge, so any round that passes cleanly is confirmed within safe dimensional limits.

At roughly 3 oz, the block is compact enough to toss in a range bag and durable enough to live on the reloading bench. Use it after every loading session, and especially when changing brass lots, bullet profiles, or dies, to catch a stuck case or an over-crimped round before it jams, cracks a case head, or damages a firing rifle.