I took my new M&P15 Sport to the range for the first time this week. I ran 190 rounds through her. I did have a few hiccups that I wanted to get your opinions on.

FYI, I did clean and oil the gun before taking her out.

1.About 30 rounds in, I pulled the trigger and it clicked but did not go off. I pulled the charging handle to clear but it was jammed shut. A fellow shooter who was familiar with AR's ended up giving the rifle a few good whacks on the table with the rear butt stock (and barrel up) while pulling the charging handle and was able to eject the round.

2.About 30 more rounds and another 30 rounds it did it again for a total of three times.

3.I then ran the rest of my rounds through her with no problem.

4.He said it could be bad ammo, oil in the bore (and grime), or a chamber that is too tight.

A question - when I oil the bolt, should I also oil the bolt head? Since I was told not to get any oil in the bore, I'm thinking the bolt head shouldn't be oiled?

Since I fired off the last 60 or so rounds w/o a problem I'm thinking it was an ammo problem. The ammo I was using is factory, but I've had it around for many years (a mix of 223 and 556). Actually some maybe reloads from a coworker but it's been so many years I can't recall.

Any opinions appreciated.

So, ammo is unknown if it is factory or reloads...is it brass cased or steel cased, or a mixture?

All brass ammo

I say No.
Oil the friction bearing parts and nothing else.
Contrary to popular fiction, ARs don't need to be bathed in oil, just like any other weapon clean and lube.
Remember, the more oil you use, the more dirt you'll collect.


Do a through cleaning and you should be fine.
It sounds like you had a dirty chamber/gas tube that cleaned it's self after a few rounds.
Might have been a piece of metal left from the milling you missed in your cleaning.
If it gives you further problems, from the symptoms you describe, I'd guess you have a partially clogged gas tube.

__________________
Hold my beer and watch this!

Thanks for the reply and great info. From what I've been reading the gas tube should be self-cleaning. If it is partially blocked, how would I go about cleaning it?

For the price, just replace the clogged tube with a new one.

__________________
Hold my beer and watch this!

is it possible that the reloads were neck sized only? Just a thought, that would make them tight in the chamber.

__________________
Grover Oathkeeper

Old ammo (usually reloads) sitting for a long period of time can swell, climate may dictate where this can happen, as I have thirteen 300 mag handloads that are swollen, don't no when or how, but I reloaded the box many years ago.
Just a thought..

__________________
Light, Accurate,Versatile M&P

Thanks for the reply. That definitely could be an issue as well. I just bought some new PMC 223 and XM193 so I'll give that a try to test for reliability.

qq - I've been doing a search for a backup / replacement carbine length gas tube for my M&P15 Sport. Will any 9 3/4" gas tube work? I see some made by Colt, DPMS, Spike, etc. I'm assuming a 9 3/4" tube from any mfg will work in the S&W (that's if I can find any in stock, everybody seems to be out ;-(

Also for kicks I've been looking at a Nickel Boron BCG. Can a new BCG just be swapped in for the original BCG or is there some adjustments / tuning required?

thanks

FYI, that procedure is referred to as "mortaring." Be sure to do this with the stock fully collapsed, or you'll bend the stock adjusting pin, making it impossible to adjust the stock.

Yes, any standard carbine-length gas tube will work.


The rule of thumb is that if you use a *used* bolt with a *used* barrel extension, you should check the headspace. But a new bolt/BCG in a used barrel extension is generally good to go.

Thanks, good to know.

thanks for the reply. Great info.

I have looked at the nickel/boron bcg..it is pretty pricey are you looking at the one from Zero Fail?

__________________
Grover Oathkeeper

If its new, and you are having problems, Smith and Wesson will fix it....and you shouldnt have ran enough ammo through it to plug up your gas tube if I read your posts correct. You are under 300 rounds in your gun. I myself would try the new ammo and see if you have any hiccups before I start replacing parts. I have never been one to replace a part just because it might be bad. This is all my opinion!

__________________
Grover Oathkeeper

I'm looking at the Spike's, which I believe ZF makes.

So far, I only have 190 rds through it. I agree, as a new gun it should work w/o me having to replace anything. I'll be taking it out again in a week. The last 60 or so rds fired (on my initial range trip) were fine, so hopefully this next trip will be problem free.

bssybeep, it is not unheard of to have problems with old ammo, I have some from the 50's surplus 8x57 that stick in the chambers of my bolt actions, the rim actually pulls off of the case. I have to use a long steel rod to remove them and i dont even shoot them anymore. Not saying your ammo is that old but if you notice ammo that is set up to store for long term is usually sealed up in air and moisture tight containers. I have a feeling you will have very few if any problems now.

__________________
Grover Oathkeeper

Shoot the XM193F at the beginning and end of your day. The preassure will clean it up, it's also the cleanest I've used to date.

__________________
Light, Accurate,Versatile M&P

Cool, hope so. Thinking about it, some of my ammo is ~30 years old. Thanks

Thanks, I'll give that a try.

If I could find 193 all the time, that's all I'd shoot. But
If freedom ammunition is as good as I've read, this may be the last ammo I ever need to order.

__________________
Light, Accurate,Versatile M&P

Here is a link that has a visual of what and where to oil and an idea of how much in those areas.

AR15 LUBE POINTS - AR15.COM

__________________
Rod
M&P 22A, 40c, 15A, 15-22

bssybeep, I had that happen to my Sport one time with reloads not long after I got it. Took a cleaning rod and mallet to get it out. Have shot both factory and reloads since with no problem, so shoot some factory loads and see if that takes care of it.

Nice. I was searching youtube looking for this exact info. thanks

I'll bet it was the reloads as well.

I will follow in agreement here. If the case was neck sized as was described previously by Oneyeopen, the brass can swell a bit more upon firing, and it will expand to the point of jamming the rifle.
It's not such an issue with most bolt rifles, because the chamber is not cleared so quickly; the pressure is long dropped. Not to mention, the chamber is likely cooler than a rifle that has just eaten up a bunch of ammo. As such, reloads do not hinder function on bolt rifles as much as autoloaders.