Extra strength buffer spring needed with heavy buffer?

[China boy]

I am building a 9mm AR pistol. I just acquired Spikes Tactical ST-9x buffer which is 8oz. Should I get an extra strength spring still? Will and AR 10 spring work? This is my first build and I'm learning the ropes.

[BillBond]

It doesn't hurt.
I always use a Wolff spring in my 9mm AR15.

[Clint]

What's the length of the skinny portion of the ST9x?

There should be enough room to run a rifle spring.

[China boy]

What's the length of the skinny portion of the ST9x?

There should be enough room to run a rifle spring.

I have not received it yet so I will have to get back to you on this.

[mack7.62]

I am building a 9mm AR pistol. I just acquired Spikes Tactical ST-9x buffer which is 8oz. Should I get an extra strength spring still? Will and AR 10 spring work? This is my first build and I'm learning the ropes.

This is like asking what kind of tires do I need for my car? Not enough info, what kind of barrel, what kind of buffer tube, what kind of BCG? I don't know much about pistols but unless you are going super short or are badly overgassed most seem to work just fine with something like an H2. Oh and no it is not a good idea to use a rifle spring in carbine length tubes, too many coils will restrict buffer travel.

[China boy]

This is like asking what kind of tires do I need for my car? Not enough info, what kind of barrel, what kind of buffer tube, what kind of BCG? I don't know much about pistols but unless you are going super short or are badly overgassed most seem to work just fine with something like an H2. Oh and no it is not a good idea to use a rifle spring in carbine length tubes, too many coils will restrict buffer travel.

Ok. I see what you are saying. Im still peacing my gun together and havent decided and barrel length. I was thinking 5-10 inches. Im not sure which bcg ill buy...im open to sugestions/explanations. Im still learning and reading a lot.

Im going to buy an extra strength spring and use it in a shockwave tube from kak.

[TheChunkNorris]

Went with a Wolff SMG spring and Spikes Buffer on a Colt 9 BCG... runs really well suppressed and non suppressed.

[Clint]

I don't know much about pistols but unless you are going super short or are badly overgassed most seem to work just fine with something like an H2. Oh and no it is not a good idea to use a rifle spring in carbine length tubes, too many coils will restrict buffer travel.

This is all true for a gas operated AR using a carbine length buffer.

However, none of it applies here as this thread is about a blowback operated 9mm.

[wanderson]

I am building a 9mm AR pistol. I just acquired Spikes Tactical ST-9x buffer which is 8oz. Should I get an extra strength spring still? Will and AR 10 spring work? This is my first build and I'm learning the ropes.

I'm running one of those in my RRA 9mm AR. I mainly shoot +P 9mm and use a Wolff Xtra power carbine spring. But with some 'range' reloads it will cycle but seems to be denting the brass on ejection and several times a case has gotten stuck in the ejection port. So I keep the stock spring on hand for light loads.

[usmcvet]

I have a 9mm lower and 16" upper that runs well with a ST-9X buffer and Wolf extra power spring. I tried it on a 5" bbl and it would not cycle. It would fire and jam. I switched back to a regular carbine spring and buffer and it ran well. I am going to try a regular carbine spring next. The ammo was the same.