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M1A magazine capacity sweet spot

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September 19, 2026, 03:32 PM
OttoSig
M1A magazine capacity sweet spot
Zero experience with the platform. What's the sweet spot for magazine size?

Are 20's the standard like 30rd AR mags?

Are 15's more comfortable? Like 20 round AR9 and Ar15 mags?

Are 25 rounders overkill?




Eight years to retirement! Just waiting!
September 19, 2026, 04:22 PM
RogueJSK
Yes, 20s are standard, and balance well.

25s are a little long but are workable.

I have a couple 10s for benched shooting/sighting.

Never tried 15s.
September 19, 2026, 09:56 PM
lyman
10's are good sometimes for bag or bench work, but the 20's work very well


never used the bigger mags, since the 20 was pretty much standard, and I have a schload of them


https://chandlersfirearms.com/chesterfield-armament/
September 20, 2026, 09:16 PM
preten2b
+1 for using the 10's off the bench.

I have also tried a few makes not made by S/A and they flex too much when fully loaded, and bulge out on sides, with a few jams. I'd say stick with the S/A.


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The plural of anecdote is not data. -Frank Kotsonis
September 21, 2026, 07:26 AM
RogueJSK
quote:
Originally posted by preten2b:
I have also tried a few makes not made by S/A and they flex too much when fully loaded, and bulge out on sides, with a few jams. I'd say stick with the S/A.


SAI doesn't make mags. SAI's mags are made for them by Checkmate, and you can get non-SAI-branded Checkmate mags for less than SAI-branded mags. They are identical magazines, other than the logos stamped on the baseplate.
September 21, 2026, 07:54 AM
OttoSig
quote:
Originally posted by RogueJSK:
SAI doesn't make mags. SAI's mags are made for them by Checkmate, and you can get non-SAI-branded Checkmate mags for less than SAI-branded mags. They are identical magazines, other than the logos stamped on the baseplate.


That’s what I’ve read. Waiting for some to come back in stock.




Eight years to retirement! Just waiting!
September 21, 2026, 08:05 AM
benny6
I use 5’s and 20’s the most. 5’s are good for shooting single feed off a sandbag, hunting, and shooting the standing stages of service rifle competitions for hand position. 20ks for everything else.


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September 22, 2026, 08:22 AM
OttoSig
Ordered a half dozen 20s to just have a few on hand. The gun shipped with one 5 rounder.

Thank you, gentlemen.




Eight years to retirement! Just waiting!
September 25, 2026, 03:42 PM
ArtieS
I have 20 and 10 rounders. As noted the 10 is best for bench shooting, while 20 is the standard.

One benefit of the 10 is that if you have guests, it limits the extent of the expensive mag dump.


"I vowed to myself to fight against evil more completely and more wholeheartedly than I ever did before. . . . That’s the only way to pay back part of that vast debt, to live up to and try to fulfill that tremendous obligation."

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October 02, 2026, 04:45 PM
D_Steve
I received the Oct News E Mail from Greg Cote today and he has the Check-Mate M1A 20 round mags in stock for $29.
In case anyone is interested.
Edit to add link: https://gregcotellc.com/cart/i...iption=1&keyword=m1a

This message has been edited. Last edited by: D_Steve,


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