This upper wear normal?

[strobro32]

My 300 BO has seen about 10K+ rounds through it on a PSA upper. Lately my carrier has been sticking in the upper. It's difficult to charge a round and some times I have to morter it to get the bolt group open.

Other carrier groups seem to work fine for a while and then it starts sticking again.

I also removed the bolt and cam pin from the carrier and the carrier still sticks in the upper.

I can not find any sign of wear on CH, carrier or bolt. I noticed this wear in the upper. There was a burr here and when I removed it, it worked fine for a bit until the burr stared forming again, within 10 charges. Is there a connection? Do I need a new upper receiver?

 

[strobro32]

I found the problem for the next guy. The gas key was just fouled.

I used a #14 drill bit and cleaned out the gas key. The gas key scraper on my AR scraping tool was not getting far enough in the key to keep it clean.

BCG glides nice and smooth now.

 

[chili17]

are you shooting lead or coated bullets?

 

[strobro32]

 

[strobro32]

I haven't been shooting PC exclusively. I was looking through my reciepts. Ive shot about 2K TNT 125s, 2K SMK 125s/220s, and 4K Leatherhead HTC subs. It's just so hard not to shoot my cast BO PC 155 grain HV rounds when it costs 6 cents a round to load. It's cheaper than 22LR.

I've probably shot about 6K PC rounds recently. Now I know what I need to clean and lubricate better.

 

[A&S Conversions]

Whenever I clean an upper, when I clean the carrier, i always clean the carrier gas key. Something to keep in mind, a steel barrel barrel is usually good for 8-10,000 rounds and chrome lined is usually good for 20-25,000 rounds. If the barrel has been Nitrided it should last somewhere between.

Scott

 

[strobro32]

Apparently 300 Blackout is different. No one is sure of the barrel life. As of this year, no one has worn one out. Using powder coated bullets has even less wear.