308kiwi

^^^^^^^^^^Ah, I didn't read/figure that, yep, I would be seriously looking at this, your dwell time is probably well short of what it needs to be. So first things first, ditch the adj gas block, you don't need it...........yet. I think you'll find the solution by sorting your gas port. The whole issue that Proof Research is trying to resolve is the issue of extended length, (more than 20"), barrels using rifle length gas systems, creating excessive dwell time and violent unlock, extraction and ejection, the same happens with the little brother rifle, 223, with extended length barrels but the volume of gas involved is far less so the issue is a lot less apparent and most people don't even notice. So, why I said you don't need your adj gas block yet is, if you at a later date suppress the rifle you may need it then to balance the gas system.

Happy New Year to you too. If your std spring and buffer are correct for the application and you're gas system is non adjustable and fitted correctly then your next step will be looking at your gas port. I'm surprised that the guy from the barrel manufacturer cannot quote you the gas port dia, FFS, they made the barrel, I'm sure they don't just randomly pluck a drill bit to drill each gas port., he should know. Anyhow, slip the gas block off and measure, accurately, the dia of the gas port. Just a little FWIW, I built an upper in 243 Win, similar case capacity, and bore dia to your 6.5 Cm, and had to go out to .095" to get it to run. There's a whole bunch of physics going on when you start tapping gases or fluids off of a supply, pressure reduction across the dia of the gas port, dwell time, (the amount of time the gas has to transfer across/through the gas port), and one that is focused on rarely, the smaller the dia of the supply, (bore dia of the barrel) vs the gas port dia the bigger the difference in the pressure drop across the gas port. All the best

I should have put something there to give a sense of scale, but yeah, these guys are huge, we'll get maybe 3 lbs of meat off this fella. The wife shot this one a while ago with her 9mm AR, to give you an idea of how big they are.....

We normally make Hare into either casseroles, (stews), or pies. Hare is such a lovely meat, rich as. We seldom eat rabbit, nothing wrong with it but our rabbits are European Greys and the meat is very very bland. I think you guys have a different species of rabbit in the US, and what we call Hare you guys call 'Jack Rabbit' please correct me if I'm wrong?

Was mucking around this morning modifying the scope mount to accept a brass catcher, just happened to have a mag full of 70gr Nosler's loaded up when this stupid hare decided to run across the field in front of our house, he did not fare well...............dinner sorted for tomorrow night.?

A merry and safe xmas and new year to you all...................from way the fuk down here almost at the bottom of the world?

NICE You forgot to tell us what suppressor you are running..........

FWIW, if you are wanting to just shoot FMJ there are a couple of loads/brands I can recommend from experience... American Eagle, (Federal) 150gr FMJ 308W PMC FMJBT 147gr 308W I have used both of these brands extensively through my Aero M5 without issue, the PMC stuff in particular is very nice ammo.

And that won't be a problem, but again you are going to want to stick with known quality 7.62x51 surplus. I have put close to 1K rounds of German M.E.N, brass cased, 147gr 7.62x51 surplus through my AR308 without a single issue, the rifle loves it but it is high quality ammo and that is key.

Sounds to me like you need to........ 1, sort your ammo, ie known quality factory ammo, and I'm particularly saying this to discourage you from shooting steel cased junk, I know many people have joy with steel cased ammo but think about it, it's made with steel cases for a reason...........budget........., if the manufacturer is cutting costs on the cases then how can you have any confidence in the remaining components from the perspective of quality and spec. 2, check/sort your entire gas system, in particular your gas tube protrusion?, your gas block, (leakage)?, alignment to the gas port in the barrel?, carrier key screws, tight?, etc etc. I wouldn't be going anywhere near your recoil system, buffer and spring, yet, other than to confirm that they are correct for the application. The BCG isn't even unlocking fully by what you have described, so not likely to be a problem with your buffer or spring, more likely an issue with the initial part of the extraction/ejection cycle, ie, unlocking and extraction, if you are having to pry the bolt open to extract the case/round then you have a serious issue with this part of the cycle, and again, this could well just be from your ammo choice. As for adjustable gas blocks, like 98 said, you don't need one for a functional rifle, once you get into suppressed DI guns then the need/want can be argued/justified, adjustable gas blocks are little more than a tuning device used to balance the gas system pressure to the 'direct blowback' effect that suppressors have on semi auto rifles which is what increases BCG speed, reducing the gas system pressure via an adjustable gas block simply balances this effect back to 'normal' BCG velocity. My 2c worth from the lower half of the planet?

The take down pins, hand guard screws and safety/selector are steel so you could send them out and have them 'satin' chrome plated. I have a friend that restores vintage motorcycles and he gets a lot of fasteners and small parts satin chromed for corrosion resistance, a good plating shop should be able to do this for you. The mag release button, aluminium, that could be tricky, best option would be to media blast it to it's base metal and then get it anodised, anodising can be done without adding the colours that we are all used to, it's the same process minus the colouring step. Media blasting can achieve all sorts of finishes depending on the media used, I have had a lot of success with very fine grade crushed garnet media, it gives a really nice 'flat' finish to stainless, be aware that if you media blast aluminium or stainless you have to use virgin media, if any ferrous metals have been blasted with the media prior you will end up with tiny ferrous particles embedded in your part and they will rust, ask me how I found that out?.

I've got one of these, great little tool, just wish I could get one for the 308 size bolt.

Oh snap. Have the same in my Rem 700 308, Timney 517 Flat trigger. very nice trigger.

If you carefully remove/radius the sharp ends on either side of the extractor hook you'll likely solve your ejection problem. You are right on the money with your diagnosis, this exact issue, with some extractors, has been discussed before.

Absolutely. Blood pressure remained stable throughout the conversation? This is the best forum to learn about these particular firearms, so much information available from a lot of guys that have done the hard yards.

Yes that is correct, if you use the extension @ 90 deg then DON'T apply the formula that I mentioned. Sorry, the context of what I was giving is that you should be aware that adding length to a torque wrench changes it's value and in many cases you simply cannot use a torque wrench with an extension @ 90 deg. So a failsafe is to use it in a straight line and do the simple maths. But you have to bear in mind that 90 deg is the only angle that you can use without applying a correction.

Exactly, I've never had to use 'shims', and god only knows how many AR's and M16's have been assembled over the last 5 or 6 decades without the need for any shims. It's just another solution looking for a problem IMO. And I particularly agree with 98Z5V, "There's so many "AR builders" that couldn't even identify a torque wrench for what it is, if you showed them a decent one" AND as a side note, when you add an extension, (barrel nut 'spanner' to a torque wrench and shift the axis of the head of the torque wrench away from the axis of the nut you MUST apply a formula to compensate for the differential between the two axis's otherwise your torque value may as well be a guess, you also MUST add the extension in the same plane as the wrench, ie not at 90 deg or any other angle, the following formula works form this problem.......... T1 = T2 x L1 / L2 T1 is the torque setting, T2 is the actual torque that will be applied, L1 is the length of the torque wrench, L2 is the length of the torque wrench WITH your extension added.

The only reason you would fit the shims between the barrel extension shoulder and the receiver face is to stop the shim/s galling and becoming deformed between the barrel nut and the barrel extension shoulder, (should you fit them there) when you tighten the barrel nut. Common sense would dictate that you fit them between the barrel nut and the barrel extension as this way would not alter the relationship between the barrel extension and the receiver. If you were to fit them between the extension and the receiver you would need to cut a segment from them to allow for the extension timing pin, just another bad idea. If I was to shim a barrel nut to align a hand guard and gas tube I would fit them between the barrel nut and the extension and use a high quality anti gall lube to prevent them moving/deforming, but the best solution is to buy a barrel nut/hand guard system that doesn't require shims, there are plenty out there.

Removing material from the front of the upper receiver will not affect head space, all it will do is move the barrel/barrel extension assembly rearward in the upper receiver, as long as you are only removing enough material, like a few thou, to true the face of the upper then it will not cause an issue. There seems to be a common belief that this is not so and that you can alter head space and/or 'set back' the chamber by doing what you are asking but I can assure you that it is nothing more than myth.

I'm running that brake on my IPSC rifle, have had plenty of different brakes on said rifle, even machined up one or two for it myself but none of them work as well as the JP. If you're worried about the step up from barrel dia to the rear face of the brake then get any competent smith to profile it for you, it's like a five minute job in a lathe, (barrel out obviously) One point to consider....if you are going to use the rifle in ISPC competition, there are restrictions on brake dimensions and the JP will put you into Open Division. Pic of mine on my rifle.......

?Oh don't I know it, but it would be a good job description to retire to

Having a tidy up in the workshop today and found these tucked away on a shelf............10% small frame forgings, a bit more involved than the more popular 80% lowers but if you want to challenge yourself........ I got 6 of these a few years ago and finished 2 into registered rifles, with sequential serial numbers, one for me and the other is the wife’s. I've attached Ray Brandes excellent PDF tutorial on finishing these lowers, it's the best info available, IMO ray brandens complete ar 15 build.pdf

I'll know I've made it in life when my job description is...............'head of crazy projects division'

IMO the Gen3 is the best Glock made, it has the largest amount of 'stuff' available for it, add a $5 'minus' connector and the trigger is leagues ahead of either the Gen4 or 5 triggers. Again IMO, the only advance that Glock has made with the Gen4&5 is the ambi features and if you're not a lefty I'd go with the Gen3

Yeah what I posted probably doesn't help with your original question, but......options dude, options?