[jeepyj]

First. It's a 6.8spc, spikes lower and palmetto upper. Just put it all together today so I had to shoot it. There's no rear sight so accuracy testing is out. I fired ten shots and everything worked the way it should. It made lots of noise, lead went downrange and it made me smile.

Here's where the question starts. All of the empty casings have a dent in the side about 1" up from the base where I presume they hit the brass deflector. The front of the deflector has some brass on it right on the 'sharp' edge. All of the casings were found in front of me at about 1:30-2:00 with the muzzle being 12:00. I think I read somewhere about that having to do with the weight of the buffer. I used a spikes T2 buffer. Should I change anything or not worry about it?

 

[BrianS]

i would check to see if the timing would be different with the 6.8SPC being different weight overall than the 5.56 i would think there would be a different timing chart.

 

[RDFABSREP]

I'd also take a look at the ejector in the bolt. It might be so stiff (brand new) that it's flinging the brass at the deflector too hard.

 

[jeepyj]

i would check to see if the timing would be different with the 6.8SPC being different weight overall than the 5.56 i would think there would be a different timing chart.

Excuse my ignorance, but I have no idea what you are talking about. I know how timing related to engines, but not rifles.

.

 

[BrianS]

 

[Tifosi]

) Give a little time for new parts to bed before getting panicy about some fantasy supertuner tweak or another.
10rds ain't anywhere close. 500~1000 would be more like it.

2) It went bang, it didn't self destruct, parts didn't fly off and rounds went down range.
Don't worry about ejection pattern for now (ever actually) but instead worry about getting sights, accustomed to the platform (ie: intimate knowledge of how the controls work), research and burn into memory relevant to the platform terms and definitions (what you did was not a function test)

POINT OF NOTE: that pie chart thing is originally based on the A1 type upper, as in no brass deflector.
As soon as brass hits a deflector the chart becomes as useless as tits on a boar hog.
Different angles and heights from various makes and even fore/aft positioning all play a role in changing pattern.

You say it patterned forward, I say it patterned aft and only went forward because it bounced off the deflector :shrug:

That aside, the dents indicate a high BCG velocity which cab 'usually' be attributed to over gassing and/or an underweight buffer

 

[jeepyj]

) Give a little time for new parts to bed before getting panicy about some fantasy supertuner tweak or another.
10rds ain't anywhere close. 500~1000 would be more like it.

2) It went bang, it didn't self destruct, parts didn't fly off and rounds went down range.
Don't worry about ejection pattern for now (ever actually) but instead worry about getting sights, accustomed to the platform (ie: intimate knowledge of how the controls work), research and burn into memory relevant to the platform terms and definitions (what you did was not a function test)

POINT OF NOTE: that pie chart thing is originally based on the A1 type upper, as in no brass deflector.
As soon as brass hits a deflector the chart becomes as useless as tits on a boar hog.
Different angles and heights from various makes and even fore/aft positioning all play a role in changing pattern.

You say it patterned forward, I say it patterned aft and only went forward because it bounced off the deflector :shrug:

That aside, the dents indicate a high BCG velocity which cab 'usually' be attributed to over gassing and/or an underweight buffer

Thanks,

I do have a lot to learn and look up.

So your short answer is 'Don't worry about it." Right?

.

 

[bpipe95]

) Give a little time for new parts to bed before getting panicy about some fantasy supertuner tweak or another. 10rds ain't anywhere close. 500~1000 would be more like it. 2) It went bang, it didn't self destruct, parts didn't fly off and rounds went down range. Don't worry about ejection pattern for now (ever actually) but instead worry about getting sights, accustomed to the platform (ie: intimate knowledge of how the controls work), research and burn into memory relevant to the platform terms and definitions (what you did was not a function test) POINT OF NOTE: that pie chart thing is originally based on the A1 type upper, as in no brass deflector. As soon as brass hits a deflector the chart becomes as useless as tits on a boar hog. Different angles and heights from various makes and even fore/aft positioning all play a role in changing pattern. You say it patterned forward, I say it patterned aft and only went forward because it bounced off the deflector :shrug: That aside, the dents indicate a high BCG velocity which cab 'usually' be attributed to over gassing and/or an underweight buffer

we usually agree but this time we don't. Have you done any gas system testing, with and adj gb? You can make the brass follow this exact diagram by taking the gun from over gassed to under gassed. It all flies true every time I have tested it.

Heavy buffers are a piss poor band-aid, heavier springs are good if you use the right spring. The weight diff in an M16 bolt is negligible when it comes to this fix. An adj GB is the only proper way to fix it.

 

[Tifosi]

short answer is 'Don't worry about it." Right?

'zactly.

An adj GB is the only proper way to fix it.

Thats just it, I don't honestly believe that there currently is anything wrong that actually 'needs' fixing.

Downside of an adjustable GB is if tuned around hotter ammo to get some mystical superpattern then its completely possible that lighter loads won't cycle the action enough to even extract, let alone throw a 'good' ejection pattern. That means more tools to haul along, the plausibility that it can ' come loose' during shooting and throw the tune out of whack, and the spooky possibility that it willl do so at the worst possible time without time or tools around leaving you holding a really spiffy looking bolt action rifle.

For the competative 3-gunner or other competition, yeah, ajustable GB and other tuning trix all day long in an effort to reduce recoil and speed up 2nd/followup shots.
For the average non~competative shooter, not so much.
For the absolute novice, it should be completely avoided until there is much more intlmacy with the platform.

Just my 2¢ of course

 

[bpipe95]

An over gassed gun is overly hard on all internal parts. It wears out springs faster, wears on bolts faster and beats up extractors faster. Most factory guns are over gassed in an attempt to get around the fact that they have poor tolerance control.

It's not for everyone but it is the correct way to do it. Also with newer units out like the syrac they are pretty much idiot proof and lend to quick adjustment. When set up correctly the first time they need zero extra maintenance. I have also noticed that when set up right a lot less carben and other spent junk comes back through the gas system.

 

[Tifosi]

And the semi related but actually OT niggle?
Who in thier right mind would ever believe that brass shhould actually come in contact with the brass deflector?

Oh, wait, right mind is usually left handed, and by God they DEMAND brass hit the deflector instead of thier face, down thier shirt, or even off thier nekkid forearm.
(which is why they developed the clip on version decades ago before eventually incorpoating it into the receiver forging proper as such were very common occurences with standard rifles and carbines)

 

[Tifosi]

Most factory guns are over gassed in an attempt to get around the fact that they have poor tolerance control.

Palmetto are very good with thier tolerances as are FN who make the barrels for Palmetto.
Gas ports have been demonstratably correct size when bounced off known standards.

Still, the 6.8 might lean a bit toward big as its not like anyone has had decades to dial in the optimum port size for a NATO standards spec roud oreven common off the shelf stuff. :shrug: