I am taking the 5.45x39mm plunge! updated 09-23-09

[subzero]

I had a long talk with Grant a while back, thinking my gun was overbuffered or undergassed. It too failed to lock open fairly often.

Long story short, the mags played a much bigger role in the situation than I thought.

Get some of the 545ar.com followers to throw in those crappy CP mags and it will help considerably.

[bubba04]

I had a long talk with Grant a while back, thinking my gun was overbuffered or undergassed. It too failed to lock open fairly often.

Long story short, the mags played a much bigger role in the situation than I thought.

Get some of the 545ar.com followers to throw in those crappy CP mags and it will help considerably.

Do you know of any vendors selling these? The website says they are no longer selling them to the public.

[Jay Cunningham]

Not locking back on an H buffer tells me it is the magazine (not a surprise). These guns will lock back on H2 and H3 buffers (unless you have a gas leak or a huge recoil spring or something like that...)

I suspect all you need to do is replace the pathetic spring with a cut-down AK-74 spring and you will be GTG. You don't need to change the follower, they actually work quite well.

[bubba04]

Not locking back on an H buffer tells me it is the magazine (not a surprise). These guns will lock back on H2 and H3 buffers (unless you have a gas leak or a huge recoil spring or something like that...)

I suspect all you need to do is replace the pathetic spring with a cut-down AK-74 spring and you will be GTG. You don't need to change the follower, they actually work quite well.

Is there some where you recommend getting ak74 springs from?

[sdacbob]

Is there some where you recommend getting ak74 springs from?

ditto

[Jay Cunningham]

If I remember right I think I just called Pro-Mag and asked them if I could have some AK-74 springs.

[bubba04]

Has anyone experimented with putting a spacer on the baseplate to give the stock springs a little more power.

I am having hell removed the front sight base. I want to put an omega rail on this beast.

[Jay Cunningham]

I am having hell removed the front sight base. I want to put an omega rail on this beast.

Unsure I understand - you know that you do not need to remove the FSB to install an Omega rail... right?

[bubba04]

Its the omega x FSB, I want to remove the hand gaurd plate on the back of it. Dont I need to remove it before I take the barrel nut off?

[justin_247]

More info on the 5.45 upper. We asked the customer that had issues with their 5.45 upper to put in a ISMI CS buffer spring and H3 to see if the bolt would lock back. It does. So I knew that we were dealing with a very large gas port. So I made a call to S&W and found out that the gas port is .073. This is HUGE. The only logic I can come up with for why they did this is because they were concerned about weak com bloc ammo no cycling (can understand this).

I am going to try and work with S&W to see if we can get them to bring the gas port down to around .068. In the mean time, if I was running this upper, I would be using an H3 buffer for certain!

C4

Did S&W ever bring the gas port down as you recommended? If not, have you found your H3 buffer w/ a CS buffer spring to be an effective remedy?

Additionally, I heard that with the new hammer spring that comes with the upper receiver, the trigger pull increases to 10-11 lbs. Is this true? If so, what can be done to bring it down to 6-7 lbs without cutting down on reliability?