Orca troubleshooting

ACWick

Kinda general info that hopefully will help someone else and also a question:
I put together an Orca from PET-CF (which is amazing...I'll post separately about that) and the build seemed to go well. Initially it would go into battery but pulling the trigger would yield a "click" but no discharge. I figured it had to be the barrel/bullet's relationship/distance to the firing pin and, initially, measuring using a standard digital caliper it appeared I was within spec; the problem I subsequently realized is that the rear of a standard digital caliper is so narrow it's tough get consistent measurements and to figure out if you're truly parallel to the surface you're measuring (or, said a different way, if you're truly perpendicular to the barrel). Depending on how I held the caliper (and depending on which face of the lower's supports I held it on) I could get measurements anywhere from 0.250 to 0.278 inches ) which are both outside of spec.
I ended up buying a digital tire tread gauge on amazon (for under $10) that had a much wider base to allow more consistent measurements. Turns out I was about 0.01 inches short of where I needed to be. I hammered the barrel in a little and it now fires properly.
The question/problem is that while it extracts the spent casing, it doesn't eject. I've read several opinions on this (obviously geared toward traditionally-purchased guns) that opined it's either "under-gassed" or the buffer weight/spring is either too heavy or too light. 🙂 Any thoughts?
Thanks in advance for any knowledge!
AW

hoffmantactical

ACWick Great job troubleshooting the first issue, barrel too far forward will do that (basically the same as the barrel melting forward).

Not ejecting is odd. Is this only during live fire? Does it eject when you manually cycle the bolt?

Sambo

ACWick I'm having a similar issue. Sometimes I'm getting a light primer strike, but when it does fire it fails to eject. It's not quite a stovepipe, but it's getting stuck in there. So I haven't bee able to get it to fully cycle yet. I'm wondering where I need to look first. My first thought is that the failure to eject points to it being under gassed. I also think the frequent light strikes are caused by the same issue you had.

Did you have any luck solving the ejection issue? What was the root cause for you?
Are you using the complete kit? That's what I'm using.
Do you have the Super Safety installed? Did that cause any issues?

hoffmantactical Do you have any advice on this?
Sidenote:
This is my first full build, so I'm sorry for botching it, but I've thoroughly enjoyed learning about the bits and pieces that make our guns go bang! And I have to glaze... The Orca is just super sexy and user friendly, wonderful design.

hoffmantactical

Sambo Having these two apparently unrelated issues is rather odd. Would definitely test in passive mode if the Super Safety is installed, that should rule out any issues it could cause.

If you have a gopro or phone that can do ₂₄₀ FPS with? That would be very valuable in telling whether or not the system is short stroking. Another way is to fire with an empty mag installed. Does the last round bolt hold open work? Check this manually as well just to confirm its not malfunctioning due to an issue with the mag or catch.

If LRBHO works, but ejection is still and issue, it could be an issue with the bolt itself. If the LRBHO is not working, I'm going to guess friction. Removing the stock and buffer system will allow you to feel how the BCG rides in the upper. Should be free to move under gravity.

Failure to fire would be as you noted, an issue with the barrel resting too far forward. Were the mounts very tight? Is there a gap between the handguard and upper? Might need to knock out the barrel and sand the mounts to fit the upper.

Obviously we'll replace any parts, such as the bolt, if they are an issue.

ACWick

Sambo I apologize for the delay in responding; life got in the way. It turns out my problem was I had used a buffer mass (from another HT kit) that was too long for the Orca build so the bolt couldn't move rearward enough to eject. I swapped the mass today and things appear to be working properly (at least in terms of ejecting) but I'll live-fire tomorrow to confirm.
As an aside to Tim, it would be helpful if the buffer masses were labeled in some way (even just a sticker on the end of each mass, particularly for people who order more than one kit at once). I may have missed this in the written or video instructions but I don't think there's any mention of the buffer mass length/weight appropriate for each build (but clearly that's mainly due to my inexperience!).
Hope this helps someone.
AW

Sambo

hoffmantactical I don't think that replacement parts will be necessary. After some more dry testing with feeding yesterday I think I've found the cause of both issues. I found that even without firing, the rounds wouldn't eject when I pull the bolt back, also causing a FTF. My assumption is that the extractor is not grabbing the round. There's a 5% chance that something is up with the bolt assembly, but I'm 95% certain now that both the light striking and failure to eject is due to the barrel not being seated far enough into the upper.

I will post an update once I sand the mounts a tad and get the barrel reinstalled.

I hope this is the issue because I just ordered a hydraulic press to help fix it.
Inshallah the barrel shall be seated.

undeadchew

ACWick In regards to the buffers I need to laser engrave my SCS and maxim delayed buffers for easy system identification.

ACWick

undeadchew Great idea!

ACWick

ACWick Huh. Well, live-fire testing didn't go as planned- the spent cartridge still fails to eject. When I manually cycle the bolt, cartridges eject fine. I'm guessing it's either under-gassed or "over-buffired" so that the BCG is not being driven far enough back by recoil to actually eject the casing. Do any of y'all with more knowledge than me (most everyone, I suspect) have any troubleshooting steps or ideas?
Thanks in advance!