Hard Charging w/Blitzkreig buffer & spring

[cecil]

Just received a Blitzkreig buffer & spring for my 9mm carbine... packing slip states the spring is a carbine spring... I installed it and now its " EXTREMLY"  hard to pull back the charging handle .. it was much easier with the original buffer & spring that came with my Stag carbine....  the new buffer spring is 2 inches longer than the original spring..  anyone have any ideas/suggestions?

 

tia

    

[L9X25]

I would try it with the original spring and see if the problem is a binding buffer or an incorrect spring.

 

I know that they recommended the AR10 Rifle length spring when I purchased mine, but I also ordered an

AR10 carbine spring since I was expecting the rifle spring to be too stiff.  What you describe sounds 

like what my rifle felt like with the rifle spring.  I replaced that with the carbine spring and it was much

better.  I later replaced that with an AR15 carbine spring and that was even better.  Feel free to test out

different springs to see what feels best.  

Edited January 6, 2018 by L9X25

[cecil]

L9X25 ... I did re-install the original spring with the Blitzkreig buffer... it was  MUCH  easier to pull the charging handle.. with the original spring my bolt locks back which was impossible with the JP spring that came with the buffer .. .  

[L9X25]

My rifle was able to be locked back with any of the springs, including the AR10 Rifle spring, but it required more effort than I think should be necessary.

 

Taccom claims that there is no reason to have an AR10 spring at all, and recommends AR15 springs.

[cecil]

L9X25... thanks.... can I use the Blitzkreig buffer with the original spring that came with my 9mm Stag carbine ??   I will look into the AR15 spring... and I plan to call Blitzkreig Monday to inquire about why its so difficult to rack the charging handle with the components I received..

 

 

[L9X25]

Shoot all of the springs that you have and decide what feels best.  You basically tune the rifle to the ammo that you are shooting.  If you shoot light loads, you can certainly shoot an AR15 spring.  Many say that factory ammo is fine too.  

[Aircooled6racer]

Hello: Blitzkrieg, 308 carbine spring works well with 131-134PF 124's. Thanks, Eric

[MikieM]

I'm wondering if loads shot from a 16 inch barrel, loads at the 130 PF mark and maybe a couple of points under, using 115 grain bullets with a slow powder, might work well with a 308 carbine spring. The recoil impulse might be just soft enough to move the bolt back to re-cock the trigger, but then the strong spring will quickly close the bolt resulting in a rapid cycle rate. 

If the last round hold open doesn't work, who cares?

Edited January 7, 2018 by MikieM

[TRUBL]

12 hours ago, L9X25 said:

My rifle was able to be locked back with any of the springs, including the AR10 Rifle spring, but it required more effort than I think should be necessary.

 

Taccom claims that there is no reason to have an AR10 spring at all, and recommends AR15 springs.

nooooo........momma says 308 springs in PCC are the devil  

[L9X25]

1 minute ago, TRUBL said:

nooooo........momma says 308 springs in PCC are the devil  

 

I reached that same conclusion by trial and error, but I hate making recommendations to people that contradict what the manufacturer of the product recommends that people use with their product.   I currently use a .223 Carbine spring in mine and feel that it is as good as anything that I have shot.

[TRUBL]

Well......I was was like.......wait a minute in 9mm a stock carbine buffer and stock carbine spring, for the most part....holds the bolt forward long enough to keep the shell from blowing up outside the chamber. BUT......a few guys had an OBD and said.......more weight!! more spring will take care of that. And they were convinced of their reason why they had OBD.....and in the name of safety, they spread that around......YOU NEED AN H3 BUFFER AND 308 SPRING and oh by the way....it's smooooooth too (yeah bull@%#$). 

 

Granted you want a spring that will keep the bolt closed for a bit and NOT let all that mass slam into the back end of your buffer tube (which is at least a 1/2 thick back there).......but going heavy and heavy, really makes that bolt slam into the barrel. 

 

In the testing we've done......up until we came out with the 3rd stage....we found that hmmmmmmm bout 20 ounces total and a 10% reduced rifle spring is really good (as long as you don't go solid on the spring)........and to be honest, we've even noticed that a full power rifle spring was a little too much.

 

Enter the 3rd stage and the recoil has gone down so dramatically that we are now looking reducing that total mass (bolt/buffer) and mmmmmmmmaybe even going to a std carbine recoil spring......but thats all secret squirrel stuff right now.

 

Soo.....that hole "momma says ........" comes from "The water Boy"

Edited January 7, 2018 by TRUBL

[noexcuses]

6 minutes ago, TRUBL said:

Well......I was was like.......wait a minute in 9mm a stock carbine buffer and stock carbine spring, for the most part....holds the bolt forward long enough to keep the shell from blowing up outside the chamber. BUT......a few guys had an OBD and said.......more weight!! more spring will take care of that. And they were convinced of their reason why they had OBD.....and in the name of safety, they spread that around......YOU NEED AN H3 BUFFER AND 308 SPRING and oh by the way....it's smooooooth too (yeah bull@%#$). 

 

Granted you want a spring that will keep the bolt closed for a bit and NOT let all that mass slam into the back end of your buffer tube (which is at least a 1/2 thick back there).......but going heavy and heavy, really makes that bolt slam into the barrel. 

 

In the testing we've done......up until we came out with the 3rd stage....we found that hmmmmmmm bout 20 ounces total and a 10% reduced rifle spring is really good (as long as you don't go solid on the spring)........and to be honest, we've even noticed that a full power rifle spring was a little too much.

 

Enter the 3rd stage and the recoil has gone down so dramatically that we are now looking reducing that total mass (bolt/buffer) and mmmmmmmmaybe even going to a std carbine recoil spring......but thats all secret squirrel stuff right now.

 

Soo.....that hole "momma says ........" comes from "The water Boy"

Tim, are you recommend pulling the weight out of the BCG? Right now I am running a KAW but have one of yours on order so interested in both setups with 130PF loads.

Edited January 7, 2018 by noexcuses

[L9X25]

When I had the JP SCS in my gun it gave me the opportunity to try about 8 different spring weights (all lighter than the stock spring) and had the ability to drastically reduce the weight of the buffer.  I first tried making the buffer heavier and it was obvious that was a bad idea pretty quick.  Soon I was as light as I could make the buffer.  Next I started reducing the buffer spring and went down about 6 lbs in spring weight to hit the sweet spot.  I was one spring away from the lightest spring they make when it felt the best.   

[TRUBL]

We've been running our bolt with out the weight and the 3 stage recoil system.......very smooth

 

[noexcuses]

I put about 300 rounds through the 3 stage recoil system (two thumbs up) last week in training and it is sweet. My hit factors scores went up quite a bit. Will have to bring hammer and punch to try it with out weight (and different springs)  at the range this coming week.

[MikieM]

Tim, you know way more about this stuff than I do, but at what point does things start becoming a little dicey after lightening the bolt in a blow-back system?

As I understand it the bolt is weighted in order to hold the case in the chamber long enough for the bullet to exit the barrel. The spring is only there to hold the bolt closed while in battery and then bring it back after the gun has fired.

Should the bolt begin to open prematurely it is possible that the case could stretch and separate. This could conceivably become easier when using weak, or worn out brass.

In any event our faces are very close to the action should any of this take place.  

[Flatland Shooter]

13 minutes ago, TRUBL said:

We've been running our bolt with out the weight and the 3 stage recoil system.......very smooth

 

 

At 14.4 oz your bolt is already pretty light.   How heavy is it without the weight? 

 

The stock bolt with your 3 stage recoil system looks like it almost 20.6 oz.  Say the weight is right at 3 oz the total system weight is now at 17.6 oz.  Right at the sweet spot others seem to like.

 

Sweet.

[TRUBL]

3 hours ago, MikieM said:

Tim, you know way more about this stuff than I do, but at what point does things start becoming a little dicey after lightening the bolt in a blow-back system?

As I understand it the bolt is weighted in order to hold the case in the chamber long enough for the bullet to exit the barrel. The spring is only there to hold the bolt closed while in battery and then bring it back after the gun has fired.

Should the bolt begin to open prematurely it is possible that the case could stretch and separate. This could conceivably become easier when using weak, or worn out brass.

In any event our faces are very close to the action should any of this take place.  

so maybe I'm old and take chances.......but being right handed and and having an ejection port on the right, pretty much shields my face. I've had OBD's on the AR9 platform, really don't like them and they kinda scare the shit out of me. But I've never broke a receiver with the 9mm round (had bullets stuck in the barrel though). But....best to go slow and go down a little bit at a time.....look at cases, make sure the bullet leaves the barrel and you should be ok. It's a learned thing I guess.....hard to explain. A chrono can help too.......cause sometimes, when you are on that edge and the bullet leaves the barrel and bounces off the front of the chrony? Things are gonna get dicey really quick.

[TRUBL]

3 hours ago, Flatland Shooter said:

 

At 14.4 oz your bolt is already pretty light.   How heavy is it without the weight? 

 

The stock bolt with your 3 stage recoil system looks like it almost 20.6 oz.  Say the weight is right at 3 oz the total system weight is now at 17.6 oz.  Right at the sweet spot others seem to like.

 

Sweet.

the slug is mehhhhh 2 ounces or so

[L9X25]

28 minutes ago, TRUBL said:

the slug is mehhhhh 2 ounces or so

Right at 2.6 oz including the roll pin.

[bwikel]

The taccom bolt is 11.9 oz without the weight. 

[HoMiE]

If you remove weight from the bolt and add it to the buffer with 3rd stage taccom buffer, you have roughly the same reciprocating mass. 

[Aircooled6racer]

Hello: Try the bolt without the weight, 308 carbine spring, Blitzkrieg, and short stroke it with 124's. It is one flat shooter. Not sure if I like it better than my JP setup but it is pretty close. This is with a 16" barrel. Thanks, Eric

[MikieM]

Just to clarify the relationship between the bolt and the buffer spring, the buffer spring only helps hold the bolt in battery. It is the mass (weight) of the bolt that keeps the case chambered until the bullet exits the barrel. Were you to reduce this bolt mass (just for the sake of argument) to the weight of the bullet, and fired the gun, the bolt would move toward the rear of the gun at the same velocity as the bullet was going away from the gun. Mr. Newton said so.

Our guns are true blow-back design weapons. There are no locking lugs, or toggles, or anything else to delay, or impede, the opening of the bolt. Only the bolt's weight. 

If you were to take the buffer and spring out of the gun, then held the gun with the muzzle pointed down and pulled the trigger, the gun would fire just fine. Granted, the bolt would slam back against the end of the tube because there was noting to damp it's movement, but none-the-less the gun would fire. If, on the other hand, you held the gun vertically (again, without the plunger and spring) gravity would pull the bolt out of battery and nothing would happen.

In addition, to holding the bolt in place the buffer spring also absorbs the energy of the rearward movement of the bolt, then releasing this energy as the bolt returns back to battery. It is during this phase that we feel the recoil of the gun. 

Hydraulic buffers (Blitzkrieg), and captured spring buffers (Taccom, MBX, and JP), all help damp this buffer spring movement making the cycle smoother, and quieter, much like the springs and shocks do on an automobile.

 

[Baltimoreed]

Newbe here. Another thread mentioned case separation at the cannulure and the need to avoid cases with them. I couldn't figure out why. Trying to run too light of a bolt for the load as mentioned could cause it. A not quite oob event would separate the case at the cannulure. My pcc is a .45 so I don't have these hot rod issues. Big and slow, like me. But I have been experimenting with extra springs under the buffer to smooth out the felt recoil. Seem to help. Am enjoying your posts, MikieM.

Edited January 8, 2018 by Baltimoreed