Buffer and spring

[blacklab]

I decided to give PCC a try, so I ordered most of the parts for a 9mm carbine build. The only thing I didn't order was the spring and buffer, I'm still not clear on what I need. The build is going to have a 16" barrel, Barrier Defense bolt and I was hoping to use the same minor load as my open gun uses. My current load is 115gr over 5.1 of Autocomp. So what spring and buffer do I need to keep the rifle flat and reliable?

I guess I should add that its going to have a fixed rifle length stock.

Edited April 15, 2018 by blacklab

[MikieM]

Here's my suggestion.

If you haven't got one already, go to Bed, Bath, and Beyonce and buy yourself a scale. A digital kitchen scale can be had for about $25, or less.

The target weight for your new bolt and buffer should be 20 ounces when using the 115 bullet at 130 Power Factor. For instance: If your bolt weighs 14.5 ounces then you will need a buffer that weighs 5.5 ounces. If your combination comes out a little heavier, don't worry about it. 

Add a Wolff Extra Power buffer spring, and you're off to the races.

 

Now. Please bear in mind that this is the way I do it, and it works. Be aware, however, that there are many other ways to do what you need done.

Have fun.  

[blacklab]

22 hours ago, MikieM said:

Here's my suggestion.

If you haven't got one already, go to Bed, Bath, and Beyonce and buy yourself a scale. A digital kitchen scale can be had for about $25, or less.

The target weight for your new bolt and buffer should be 20 ounces when using the 115 bullet at 130 Power Factor. For instance: If your bolt weighs 14.5 ounces then you will need a buffer that weighs 5.5 ounces. If your combination comes out a little heavier, don't worry about it. 

Add a Wolff Extra Power buffer spring, and you're off to the races.

 

Now. Please bear in mind that this is the way I do it, and it works. Be aware, however, that there are many other ways to do what you need done.

Have fun.  

Ok, I already have a scale. This sounds like a good place to start. I'm assuming I should use a rifle length buffer?

[alvinsmith75]

13 minutes ago, blacklab said:

Ok, I already have a scale. This sounds like a good place to start. I'm assuming I should use a rifle length buffer?

I just recently installed a rifle length buffer tube as well. Smoke Composites to be exact. I also purchased the spacer to be used with the carbine buffer and spring.

[Flatland Shooter]

26 minutes ago, blacklab said:

Ok, I already have a scale. This sounds like a good place to start. I'm assuming I should use a rifle length buffer?

 

Alvinsmith covered it better than I did. 

 

Since you are building a carbine, why not use a carbine buffer.  You will also have a nice selection of buttstocks to choose from.  That said, I do have one 9mm lower with a rifle buttstock but found I prefer an adjustable carbine stock.

Edited April 16, 2018 by Flatland Shooter

[blacklab]

9 minutes ago, Flatland Shooter said:

 

You can but then you need to run a rifle buffer (longer) or run carbine buffer (shorter) with a spacer behind the buffer spring.

 

Since you are building a carbine, why not use a carbine buffer.  You will also have a nice selection of buttstocks to choose from.  That said, I do have one 9mm lower with a rifle buttstock but found I prefer an adjustable carbine stock.

I use Ace stocks on my 3 gun rifles. I like the feel of them so I thought I would use the same for my 9mm build.

[Flatland Shooter]

I too have several guns with Ace stocks.  After a while I decided to try an adjustable (carbine) stock and now really prefer it.  Turns out the Ace was just a hair too long for me.  

 

I usually have the adjustable stock set just a bit shorter than the Ace stocks and do well with it,   On classifier stages with the buttstock starting on the belt, I shorten the stock and additional one notch. 

 

Maybe its just me.

 

Nice thing about the AR platform, you can switch around parts like crazy until you find the perfect fit.

[blacklab]

I tried using an adjustable stock but I think I did more harm then good. I seem to do better keeping everything the same all the time. But, everyone is different and like you said AR's can be built for each persons liking. The only time I wish I had an adjustable stock is when it's 10 degrees out and I have 6 layers of clothe on. Then the Ace is a little long.

[MikieM]

8 hours ago, blacklab said:

Ok, I already have a scale. This sounds like a good place to start. I'm assuming I should use a rifle length buffer?

 

If you mean buffer tube, then it's up to you. Most everyone uses a carbine length tube.

If you use a 5.5 ounce buffer you will need a spacer. Spikes has them, as well a New Frontier. You could use a small stack of quarters but that is adding unnecessary weight. You want your bolt to come back about a quarter inch past the bolt catch.

A 6 ounce buffer and an Xtra power spring solves all of your problems. No spacers.

A good target weight for your gun is 6 pounds. If you are young and strong a little heavier won't hurt a thing. If you are old and frail (like me) then you'll want to watch the weight as you build. 

 

[Stuntman]

Could the Vltor A5 H4, H5 buffers work for 9mm?  They are 6.08 and 6.83 oz respectively.  Plus the extra length would eliminate the need for a spacer.

 

[BartCarter]

The Vltor is 4.00 inches long, making it the right length for the carbine buffer tube.  They come in 3.8, 4.56, 5.33, 6.08 and 6.83 ounces.  They have reciprocating weights in them that can be changed out to make a custom weight.

 

I have tried multiple combinations of heavier springs, lighter springs, heavier buffers, lighter buffers, spring loaded buffers, dead weight buffers, solid buffers.  What works for me is around 20.2 oz with a carbine spring.  Less sight movement and less felt recoil. For example one PCC has a Law Tactical with 14.36 oz in the bolt minus weight plus piston and a Vltor A5 H1 4.56 oz buffer. I believe in moving weights in the buffer for a dead blow effect.  I shoot Fiocchi 9 mm FMJ factory loads. YMMV

[MikieM]

7 hours ago, Stuntman said:

Could the Vltor A5 H4, H5 buffers work for 9mm?  They are 6.08 and 6.83 oz respectively.  Plus the extra length would eliminate the need for a spacer.

 

 

Absolutely. Good choice.