what kind of drop in pressure can I exspect shooting .308s in a garand with a sleeved '06 chamber,,the navy sleeved thier garands when the gov. went with the 7.62x51 nato in m-14s and m60's,,etc.

the 308 is loaded to higher chamber pressure than the 30-06,thats why it's ballistics [read velocity's] are so similar.

If the sleeving was well done and the 308 chamber a decent chamber, you should not see any presure drop from, say, a similarly chambered original 308 rifle.

I am pretty sure you may need to do more than sleeve the chambers. Garand 30-06 loads where loaded to much lower pressure than current 308 or 7.62 nato, you run the risk of bending an OP rod unless you change the charging spring. But a great many M1's went on to be 308s without much ado, but this begs the question "Why?" As is the Garand is accurate and has plenty of killing power for hunting, it would be a shame to have to spend money like that if you didn't have to.

quote:

Originally posted by Big Bore Boar Hunter:
I am pretty sure you may need to do more than sleeve the chambers. Garand 30-06 loads where loaded to much lower pressure than current 308 or 7.62 nato, you run the risk of bending an OP rod unless you change the charging spring.

The important pressure in a Garand is the MUZZLE pressure (gas port pressure). Fast powders don't produce enough, slow powders produce to much, and medium powders produce just the right amount.
The biggest bender of Op Rods was launching grenades (enough so that that they modified the earlier op-rods to handle the extra strain IE: the so called "cut" vs "un-cut" rods).

Maybe BS, the Navy conversion was contracted through HP White, they used an insert and drilled out the gas port to handle the difference in "port " pressure. In addition a rejection block was later placed in the magazine to prevent loading of -06 cartridges. Later they found the chamber inserts were ejecting, so groves were reamed in the original chamber to hold the plug. Modern smiths usually loctite them in. Still, action pressure between the cartridges are different. Maybe next I should be more specific to keep the a-holes at bay.