I recently purchased two 20LR round PMAG's for my new .308 from WeaponsWorld.com for 19.95 but havent found a 4 or 5 round magazine for legal hunting. I'm not sure where to look. Any suggestions on where I might find one?

4-Round AR .308 Magazines | Rifle Magazines at Brownells

S&W has them, but they are back ordered.
We can hunt with only 5 round mags in Oregon.

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it's 10rds here in Missouri, I have been waiting for the promised Pmag 10LR.

Last season I used a magazine limiter in my AR15, so I know that is legal. f the 10LR doesn't become available in time, I will modify one of my 20LRs.

I am just not interested in a steel 10rd mag, no real reason, just don't want one

Just received 5 round magazines from Midwest PX yesterday. I must have got some of the last few, as they now show unavailable. MidwestPX.com
Have not test fired them yet, but they load, fit and cycle through the weapon perfectly.

They can still modify your PMags if you send them in. MidwestPX.com

Midway has DPMS 4 round in stock.

Well the “mid 2013” timeline Magpul gave for the 10LR magazines has come and gone, and firearms season here in Missouri starts in 3 weeks.
I have previously stated I had no interest in a lower capacity steel magazine and I didn’t really want to permanently alter a perfectly good 20LR, so it is time to “put something together”.
I DO NOT know what your local and state laws are in regards to magazine capacities and what can be done to be compliant. I have seen threads from California of rivets’ and epoxy to be compliant.
I do know, however, that in Missouri, you can only hunt with a magazine with a capacity of no more than 10. This can be done with limiters or blockers…. Think shotgun plug to limit a shotgun to three.
The limiting device I used was a piece of ½” airline tubing, but anything you can get to stay in the recess shown should work just fine. Note how the mag spring is considerably smaller that the follower.

The MidwestPX magazines that I received have the base plates permanently attached with roll pins. I am guessing that is so they would be considered "permanently" altered which some states may require.
Here is Nebraskas rule for magazine capacity for big game hunting, "Semi-automatic firearms capable of holding more than six cartridges are illegal". Those who have checked with the Nebraska Game & Parks have been told that as long as the magazine will not hold more than five rounds it is legal, permanent modification of the magazine is not needed.
Ole-cowboy's "This can be done with limiters or blockers…. Think shotgun plug to limit a shotgun to three." would be legal, at least here in Nebraska.
Check you local and state regulations very carefully!