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1/25/2018 7:38:29 AM
Posted: 2/16/2006 4:36:39 PM EST
I am finally getting around to loading for my .300. I have had it together for over 6 months and decidedI should actually go shoot it. Anyway, today I made 5 dummy rounds with Sierra 220gr Match Kings to make sure they would chamber correctly. I loaded them into a 10 round mag and they were really loose, sliding back and forth. I tried them in a different mag and they were tighter but not the tight I'm use to with .223 rounds. What could be the cause and what can I do or is this somewhat normal? I noticed in the really loose mag the bolt tends to just slide over the rounds instead of chambering them. I've heard something before about bending the feed lips but I don't remember enough to just go tweaking things yet. Thanks.

Link Posted: 2/16/2006 6:20:19 PM EST
I use regular 20 and 30 rnd GI mags and the rounds fit without any slop in the mag, you shouldnt need to mod the magazine at all. I am using Sierra 240g matchking .
Link Posted: 2/16/2006 10:27:00 PM EST
What is your OAL on the loaded rounds?
Link Posted: 2/17/2006 3:59:46 AM EST
[Last Edit: 2/17/2006 4:00:49 AM EST by nrode]

Originally Posted By Scollins:
What is your OAL on the loaded rounds?

I had to go down to 2.225 OAL to get them to chamber.
Link Posted: 2/19/2006 5:42:13 AM EST
I load my .300/221 to the same OAL as .223... about 2.20" - 2.25" with bullets long enough to be seated that far out. Shorter bullets (125 gr. mostly) have a shorter OAL when loaded. This has never posed a problem with either the longer or shorter OAL.

Your problem sounds mag related. Get some new 20 rd mags (they work fine off a bench or bipod) or if you have a bunch of older 20 rd mags, go with Wolff mag springs.

Link Posted: 2/20/2006 4:00:51 PM EST
What's the magazine capacity of the .300 whisper compared to a .223? How 'bout bullet weight?
Link Posted: 2/20/2006 4:03:22 PM EST
I use corbon 220 subsonic in standard GI mags with zero problems. I've read some guys lower the front lip of the mag a mm or two for the big bullets, but mines does not seem to need it.
Link Posted: 2/20/2006 4:39:44 PM EST
Link Posted: 2/20/2006 5:54:12 PM EST
Thanks, pretty cool. In regards to bullet weight, I meant like rounds per pound; i.e. 168gr 7.62 weighs ~ 20 rounds/lb. Just curious.
Link Posted: 2/20/2006 7:16:09 PM EST
Link Posted: 2/21/2006 5:22:48 AM EST
Sweet, thank you sir. Once I get out of school and start making bank I'll probably be mailing you a check for a upper.
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