holdover
.475 A&M Magnum
I can run to home depot and get some in the morning . no biggie.
Any gun smiths on this board in WNY?
- Thread starter holdover
- Start date
Acer-m14
20×102mm Vulcan
yep take the upper off .. and any other parts as needed .. .. remove the gas block .. ..
chamber a spent case .. kiss the muzzle and blow
holdover
.475 A&M Magnum
Got pair of calipers this morning , took the rifle apart.
holdover
.475 A&M Magnum
I ordered a new gas block . This BCM , gas block is to much to deal with. Im going to wait till I get my new block before reassembling.
ordered a Daniel Defense clamp on .
ordered a Daniel Defense clamp on .
meketrefe
.450/400 Nitro Ex
Why did you order a gas block wo knowing where the issue is, still?
Take off the block assembly and blow down the gas tube and you should have plenty of air but you probably don't.
Then repeat the same test as yesterday in the barrel and you should have planty of air coming out the barrel port.
When ordering a gas block ideally made of steel and clamp type only.
Something simple made of stainless steel, small, light and with the clamp type that is the best one can use.
Forget about expensive fancy looking stuff that servers no purpose and stay away of set screw gas blocks of any kind.
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Whatcha need PM me
holdover
.475 A&M Magnum
I ordered the new block because the one I have is a major pain in the ass taking it on and off. It wasn't a quality issue, BCM makes good stuff.
I even heated it like you said. it just doesnt want to move. Its a 750, and so is my barrel .
Ok,I got a can of air, I blew air down the gas tube , and it came through the gas block fine. There doesn't seem to be any blockage in the tube .
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meketrefe
.450/400 Nitro Ex
I ordered the new block because the one I have is a major pain in the ass taking it on and off. It wasn't a quality issue, BCM makes good stuff.
I even heated it like you said. it just doesnt want to move. Its a 750, and so is my barrel .
Ok,I got a can of air, I blew air down the gas tube , and it came through the gas block fine. There doesn't seem to be any blockage in the tube .
View attachment 89320
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Shop rifle parts (2,606) at Brownells, including barrels, stocks, triggers, and bolt carriers to customize, repair, or upgrade your rifle’s performance.
So if the block and tube let the pressure pass through the only things possible left are:
A) when you blow in the barrel the port is blocked, which I doubt.
B) when you installed the block you either didn't match the bleeding holes or the barrel or the gas block ports
are in the wrong place overlapping and essentially canceling the flow of gas.
Blow on the barrel and you should notice the air coming out and this way discard option A). if you have a clip or a whire something
you can find to be a tight fit in the port (ideal mild steel) put in the port and then tell me the diameter
from the calipers. It should be fine but lets verify.
I have a lathe if you need it bored out a touch
Pm sent
holdover
.475 A&M Magnum
Looks like the port hole in the barrel is about 2mm. The air flowed through the port hole on the barrel , no obvious problems there.
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Saltwater60
20×102mm Vulcan
I’d be willing to do the samething mentioned above. I have a drill press and lots of drill bits. If you know what you need to do I can get a set of calipers from my BIL or you can buy the drill bit. I’d be willing to help for free no money needed.
I have an air compressor too.
Oh and I’m just north of Buffalo area. Not sure where you’re at.
holdover
.475 A&M Magnum
I appreciate the offer guys, but we need to get it diagnosed before we operate. Lets see where were at .
and I would insist on paying yous for any help rendered.
and I would insist on paying yous for any help rendered.
holdover
.475 A&M Magnum
The barrel is 18 inches, the gas hole is 4.8, inches from the crown , the gas hole is 2mm
meketrefe
.450/400 Nitro Ex
The measure relative to the muzzle doesn't say much. you need to make sure the ports are in the
same location relative to the barrel cut that works as a stop for the block and obviously the port
in the barrel is in line with the key in the barrel extension (perfectly vertical)... and it should.
yesterday the air would not flow as installed and with everything apart it flows w/o problems in
every part so the problem is the installation or porting location.
forget about the witness mark on the other side of the gas block and lets measure where the
port on the gas block is and where the port is in the barrel relative to the stop. measure from
the barrel cut/stop to the port first and write it down.
Then measure from the end of the gas block to the port in the gas block. The gas block port,hole
should be much larger than the port so it has some tolerances to locate and mate them but
if, lets say, the gas block is a tad longer in the front end it might cover the port after installed
and the reason for it to block the gases.
Don't drill anything, don't cut anything, simply measure. it has to be either the barrel port location
mistake (which I doubt) or the gas block witness mark cannot be trusted or the block in fact drilled
in the wrong place. If you have a close up picture of either or the block or just the measures
we should be getting the final diagnosis here pretty soon.
Since this block gave you grief might not be easy to see if the witness marks aligns with the barrel port
and then turn it 180 but also the witness mark needs to be drilled vertical with the port in the block
so better just meaure and use a slight mark on barrel and block to line things up where they should land.
The location and alignment of the port is critical as you might already know.
Robin
.577 Tyrannosaur.
I wouldn't take money. This kind of problem solving is fun.
Robin
Robin
White Oak puts a dimple at the bottom of the barrel as a witness mark for aligning A2 front sight tower (which is also traditional gas block). Holdover uses that dimple to align aftermarket gas blocks. The alignment point is not necessarily the same for all gas ports.
spat
.950 JDJ
I would use the correctly sized drill bit as a gauge pin to check the size and make sure the hole is clear.
If it was undersized I would consider correcting it myself, but I would not just "make it bigger because it's not working".
holdover
.475 A&M Magnum
Something I had not considered before is that my lower is a carbine but the barrel is 18 inches , almost rifle. I dont know if that can be part of the problem . My 16 inch upper shoots fine with either bolt with the same lower. But I would think putting a heavier buffer spring would do nothing.
Opinions?
Opinions?
That does not make a difference.
holdover
.475 A&M Magnum
Looks like I bought a $300 club, with an effective range of 2 feet
holdover
.475 A&M Magnum
Wondering if the brand new receiver could be a problem. Could it be too tight on the BCG causing enough friction to slow it down? IS there a good way to polish it? Just throwing some Ideas out there.
meketrefe
.450/400 Nitro Ex
Holdover. Before you were not getting any gas into the bolt so now you do and it short-cycles? if so, two complete differnt things. We need to go step by step to understand. Where are you in the process right now?
meketrefe
.450/400 Nitro Ex
Btw... For a 16" or 18" carbine length is possible but mid length is best. For 18" rifle is even better than mid length.
Even a 16" runs very well and cool and less pressure with a rifle length porting. Every length will require the correct porting.
Carbine length porting should be avoided in any barrel but it doest mean it cannot work, it is just hotter and harder to balance.
Even a 16" runs very well and cool and less pressure with a rifle length porting. Every length will require the correct porting.
Carbine length porting should be avoided in any barrel but it doest mean it cannot work, it is just hotter and harder to balance.
holdover
.475 A&M Magnum
Well Im not exactly sure what the problem is. rifle will fire one round. round does not extract, nor reload. What I call tell the gas system is moving air through it , Does not seem to be any blockage, Cant figure it. the dimple on the bottom of barrel is not in line with the gas hole . At first I lined it up to the dimple , didnt work . then I placed a small allen wrench into the hole on the gas block itself , I marked the wrench with a razorblade and used that as a guide to line up the hole , it seems like the gas block wants to go back deeper a smidge . then I tried lineing up the screwhole on the bottom of the gas block to the gasport hole marked it , spun it around , Nothing . same thing. Im almost out of blanks at the moment , 2 left .
The BCG fires fine with my carbine upper , so I think I can eliminate that. The Bravo co upper receiver is brand new , Cant figure why that would be a problem . the gas tube is new, Its a mid length , sprayed air in tube, no leaks , Placed an empty round in chamber and sprayed air through gas tube from inside the receiver , air came out from front of the barrel and some from where I was spraying.
For whatever reason, it seems to not be getting enough gas .
Signed baffled in Buffalo.
1075tech
.338 Win Mag
You are trying this with blanks?
holdover
.475 A&M Magnum
Yes, the neighbors frown on using live rounds in the yard.
holdover
.475 A&M Magnum
Ive taken it to the range once, live rounds , but same thing thing
spat
.950 JDJ
No rifle is going to cycle with blanks unless you are using a blank fire adapter like this.
AR-15/M16 Blank-Firing Adapter
The AR-15 Blank Fire Adapter is designed to allow you to create enough backpressure to cycle your AR-15 when using blank ammunition. The blank fire adapter easily slips over the flash hider of your rifle and can be adjusted to find the correct amount of backpressure for your rifle.
www.keepshooting.com
Without the bullet providing a restriction the gas pressure in the barrel is a tiny fraction of what it should be.
spat
.950 JDJ
Before or after correcting the gas port alignment problem ?