308kiwi

H4350 is made by ADI in Australia for Hodgdon, ADI call it AR2209, it's a very popular powder here, especially in the likes of 243 Win, 260 Rem, 7mm-08 and now the hipster 6.5 CM, I guess it would also perform well in the latest wonder, 6mm CM I use it in 243 Win and 6mm Rem, it's my 'perfect powder' for these calibres ?

We were there October 2016, the whole rear of the flight deck is a space museum, the shuttle, a lunar capsule, heaps and heaps of stuff from the space program, just so cool to see it all close up.

Totally, one of the highlights of our weekend in New York.

Yeah I was surprised as well, I mean it's big in it's own way but until I saw it in the flesh all I had ever seen was pics and video and yeah that sure doesn't offer scale. Lots and lots of other very cool aircraft on board as well, including the space shuttle Enterprise, we spent hours looking around, I'm very fortunate to have a wife that loves the same things I do so there was no hurry?

When we were in New York we went on board the USS Intrepid, there is an SR71 on the flight deck, very freakin cool to walk around it.

^^^ spot on. If you are going to go past 20" barrel length you really need a longer, (than std AR rifle length), gas tube to keep your dwell time in check, a std rifle length gas system on a 24" barrel will cause you issues with extraction and brass life, ie friggin hard on brass and extractors as the gas system is starting the unlock and primary extraction too early. Also going with a custom barrel you can sort your throat length at the same time as chambering, most of the accuracy issues with these 6mm and 6.5mm 'wildcats' is or can often be sourced back to incorrect/inadequate throat length for the projectiles and one can only assume you are going to be using 105 -115gr VLD's if you are building this for PRS competition. When I built my 243 Win upper I shifted the throat forward by .040" with a throating reamer after I finished reaming the chamber, result being more options with seating depth and lead in the throat. In saying that, you are going to be limited with seating depths anyway because you will need to be seating for mag length, but still, point stands.

https://www.brownells.com/rifle-parts/barrel-parts/rifle-barrels/ar-308-barrel-6mm-creedmoor-heavy-profile-prod110185.aspx Pretty good review on this one.^^ IMO if you want something specific then buy yourself a BAT Machine 308 barrel extension, a Krieger or a Bartlein 6mm blank in the twist you want for the projectiles you are going to use and get it threaded, profiled and chambered by a gunsmith that knows what he is doing.

OK, so I'll wade in to the porous vs not porous debate? Any of you ever seen the inside of an industrial/agricultural/truck transmission or engine crankcase?, if you have you may have wondered why the manufacturer bothered to paint the inside of the transmission housing/crankcase. Well there are a handful of very good reasons why they do. 1...the paint encapsulates any stray sand from the moulding/casting process used in the manufacture of the housing. 2...the paint reduces surface tension, (makes the surface slick), and the lubrication oil drains to the bottom more readily so when being serviced more of the oil is removed on draining. 3... and here's the clincher, the paint SEALS the housing, preventing oil seepage through the casting at high operating temperatures. I have seen it with my own eyes, ZF APL345 axle, blistering the exterior paint, poked the blisters and oil poured out of them, after pulling the axle apart it was apparent that parts of the inside surfaces had been missed when it was painted, guess what, this is exactly where the oil blisters were located on the outside of the housing.

Like 98 says, two different systems. The Glock mag feeds from the centre of the mag, the Colt/Uzi mags feed left and right alternatively, so the bolts are different, ie they have a different width relief machined on the bottom of the bolt to clear the feed lips, depending on what mag system they are designed for. I know you say your bolt is supposed to be 'both', but it sure as fuk sounds like this is your problem, the mag feed lips are contacting the bolt as it goes into battery, this also explains why you are having 'some' success when you lower the adapter block, effectively lowering the mag feed lips in relation to the bolt. I've modified quite a few of these bolts so that they work with Glock mags, only way I've found to sort this issue.

She ate the whole damn thing except the ears, then slept for two days

My best hunter, Sooty bringing home her own dinner............

Thank you. It's really interesting comparing the actual 'gain in area' increases as your port size increases, something to always consider when tuning gas ports.

I can't add to the "barrel gas ports" thread because it's read only but 98 has posted a couple of charts on there recently, this is another that is a handy reference, someone that can add to that thread could perhaps attach it. Cheers..

I got my grubby little mits on a couple of these...............they are freakin awesome. https://www.bte-usa.com/2nd-generation-tanker-strong-side-gas-de

It wouldn't surprise me if most of you lot were on a no fly list.

One day no doubt. We have been talking about another trip to the USA, won't be this year, unless the exchange rate does something miraculous, @$1.50 to the $1 it's a killer at the moment.

If only, we are in the middle of baleage and silage season which = flat out fixing mowers, balers and tractors, making winter feed for our agricultural sector, I have a better chance of winning the lottery than getting leave.

Much jealous, I'd frickin love to go to Shot Show.

Very small dia carbide reamers have a tendency to break very very easily, removing broken carbide reamers from what is effectively a blind hole is a difficult task. Totally agree with Matt Cross, a HSS drill bit of the correct diameter is all that is required.

Check that your barrel extension is flush with the rear lower face of your upper receiver as shown in the attached pic, if it isn't then this is another reason why your buffer can be contacting the retainer detent. it can be fixed by removing, in a lathe, the offending amount from the front of the receiver threads effectively shifting the extension/barrel rearward to it's correct position.

It's mildly concerning that you are even doing the maths on this.

^^^^^^^^^^^^^^what he said. The quarters , effectively a spacer, are to compensate for a buffer tube that is too deep or a buffer that is too short and also gives you the opportunity to tune the travel of the buffer so as to not hammer the living crap out of your bolt catch and/or to prevent the carrier contacting the lower. Regardless of what spring you use, (assuming said spring doesn't go into coil bind in compression), the relationship of the buffer to the tube will not change so yes you should keep them in place.

Fair call, and one would think that would be the easiest thing to get right but it seems not to be so, simply going by the number of times the topic of buffers and springs comes up on here.? Make a trip here as your retirement present to yourself and I'll show you the kiwi "number 8 wire" solution to every engineering problem ever encountered.

This chart is laminated and pinned on the wall in my workshop it has some of the BEST information available anywhere AND directly relates to what I said earlier re the physics of what goes on at the gas port, in particular the relationship of the bore dia vs gas port dia and the relationship of the bore, gas post dia and the length, (wall thickness of the barrel) of the gas port and of course that all important dwell time relationship. I'd agree, I went through this with my 243, like I've said, and ended up @ .095", it runs 100% and is a total pussycat to shoot. It's all one great big balancing act, and the biggest problem is when the symptom is fixed rather than the cause which seems to be the norm with the AR family, people don't get the right info, and this includes manufacturers in some cases, and just keep changing poop until it runs, I call this process 'swapnostics'. I am a firm believer in 'start at the beginning' and as far as cycling issues with these rifles is concerned that is the gas port.