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D53
10-03-2009, 3:32 PM
Ok so like all my questions, I have searched the forum and I have searched using google. But I was curious if there is any real differance in a standard AR buffer spring and a AR 9mm buffer spring? I have seen people selling AR15 9mm buffer springs, but the spring rate is the same as a .223 spring, so what is the differance. I only ask because I don't want to buy an extra spring if one that come with a stock will work fine. Thanks in advance for any info.

On a side note I do understand that you need to upgrade the buffer to a 9mm buffer and that the hammer needs to be changed out.

Actually thinking about it, here is another question. I have read plenty of threads here and on other boards of people using the DPMS LPK on a 9mm AR and not having to change out the hammer for a 9mm specific hammer and not having to ramp the bolt carrier. Some people say it works flawlessly, and some, not the majority, say that you need to ramp the BC or you will break the pins. Just curious on those who have actually ran the DPMS LPK with the stock hammer and have had no problems and how many rounds have you sent down range?

Josh3239
10-03-2009, 3:48 PM
9mm buffer spring? No, the 9mm buffer alone should take care of the amount of weight needed to put on the 9mm BCG. A regular spring will do just fine.

A regular hammer with a non-ramped carrier will lead to much faster wear. The notch on the regular hammer can also catch the BCG and stop it from closing. Doing this excessively can put stress on the hammer pins, which will then put stress on the hammer pin holes in your receiver. The worst thing that can happen is you bolt won't close and you'll probably break your hammer pin faster and maybe open your receiver pin holes up.

Get a 9mm hammer and a regular 9mm BCG or use the regular hammer and a 9mm BCG that has been ramped.

D53
10-03-2009, 4:07 PM
9mm buffer spring? No, the 9mm buffer alone should take care of the amount of weight needed to put on the 9mm BCG. A regular spring will do just fine.

thats what I figured, but I though I would just ask to make sure, thanks for the info.

supermario
10-03-2009, 4:50 PM
if you buy a CMMG upper or the Cmmg BCG, it comes with a ramp and can be used with the standard 556 hammer. Also i believe you can use the heaviest 556 buffer and it will work on a 9mm also. One guy on here just posted that he ran a heavy buffer on his 9mm and it works fine!

CHS
10-03-2009, 5:24 PM
Ok, here's the deal:

The spring is just a normal spring. No differences there.

The 9mm buffer is MUCH heavier than a carbine buffer and is definitely needed.

A DPMS (no-notch) hammer will work fine with a non-ramped bolt, however it will wear out the hammer pin hole faster than normal due to how much lower on the fulcrum the bolt hits the hammer. On a non-ramped bolt, it's ideal to have the 9mm-specific hammer.

A notched hammer WILL NOT WORK with a 9mm bolt and will catch the bolt, making it almost impossible to seperate the upper from the lower. DO NOT USE a notched hammer with a non-ramped 9mm bolt.

With a ramped bolt you DONT and normally CANT use a 9mm hammer.

The IDEAL setup is a ramped 9mm bolt and a DPMS no-notch hammer.

My idea of a perfect 9mm upper:
- Spikes tactical billet flat-top 9mm upper receiver
- Colt or CMMG chrome-lined 16" barrel
- Ramped Colt or CMMG bolt

Lower:
- DPMS no-notch hammer, or modified Colt M16 hammer (remove the sear catch off the rear)
- KNS gen-2 anti-walk/anti-rotation pins
- Standard 9mm buffer (Colt or RRA)
- Spikes Tactical 9mm buffer tube spacer/bumper (restricts rearward movement of the buffer)

D53
10-04-2009, 6:11 AM
Right on, thanks for all the info guys!

redcliff
10-04-2009, 6:52 AM
Ok, here's the deal:

The spring is just a normal spring. No differences there.

The 9mm buffer is MUCH heavier than a carbine buffer and is definitely needed.

A DPMS (no-notch) hammer will work fine with a non-ramped bolt, however it will wear out the hammer pin hole faster than normal due to how much lower on the fulcrum the bolt hits the hammer. On a non-ramped bolt, it's ideal to have the 9mm-specific hammer.

A notched hammer WILL NOT WORK with a 9mm bolt and will catch the bolt, making it almost impossible to seperate the upper from the lower. DO NOT USE a notched hammer with a non-ramped 9mm bolt.

With a ramped bolt you DONT and normally CANT use a 9mm hammer.

The IDEAL setup is a ramped 9mm bolt and a DPMS no-notch hammer.

My idea of a perfect 9mm upper:
- Spikes tactical billet flat-top 9mm upper receiver
- Colt or CMMG chrome-lined 16" barrel
- Ramped Colt or CMMG bolt

Lower:
- DPMS no-notch hammer, or modified Colt M16 hammer (remove the sear catch off the rear)
- KNS gen-2 anti-walk/anti-rotation pins
- Standard 9mm buffer (Colt or RRA)
- Spikes Tactical 9mm buffer tube spacer/bumper (restricts rearward movement of the buffer)

The "ideal" set-up is exactly what I have and it works flawlessly, except I don't have the 9mm buffer tube spacer... which I imagine is to prevent damage to the bolt hold open.

However since I use a r.a.w. lower and a VM-hytech Uzi mag block with pre-ban uzi mags I'm not using the bolt hold-open anyway.

supermario
10-04-2009, 1:14 PM
I thought the 9mm spacer was originally made for the A2 stocks becus of their extended length, I read it was not neccessary for the short carbine length? Just what i read and sharing this info, not sure if its correct?

Josh3239
10-04-2009, 2:06 PM
That sounds right to me.

yasushi
10-04-2009, 2:36 PM
I thought the 9mm spacer was originally made for the A2 stocks becus of their extended length, I read it was not neccessary for the short carbine length? Just what i read and sharing this info, not sure if its correct?

9mm buffer and the spring is the same set up on both A2 and carbine stocks and the spacer is meant to take up the difference between A2 and carbine tubes. If you are using a carbine stock, spacer is not needed. I'm not even sure you can cycle the bolt if you put the buffer spacer in the carbine stock..??

CHS
10-04-2009, 3:53 PM
I thought the 9mm spacer was originally made for the A2 stocks becus of their extended length, I read it was not neccessary for the short carbine length? Just what i read and sharing this info, not sure if its correct?

The Spikes tactical spacer is designed for carbine buffer tube 9mm set-ups.

Basically, in normal operation the 9mm bolt travels as much as a regular 5.56 bolt, but it doesn't need to since a 9mm cartridge is about 1/3 as long as a 5.56 cartridge. What the buffer does is limit the travel of the 9mm buffer to "tune" it properly to the length of stroke needed for proper 9mm operation. The use of the buffer also leads to decreased wear on things like the bolt catch.

Don't confuse it with the A2 buttstock spacer needed for fixed-stock 9mm's.