willbird

This is trajectory for the 10.5 with the Hornady 108 ELD match.

The end result will probably end up a lot like this 5.56 setup, I really like the ALG rail of that style, they stopped making that exact model. The idea of just using it as 14.5 comes to mind too, or 12" or some other number...we will see once we have the raw materials at hand :-).

I was looking at the ballistics by the inch chart 98 posted for 6mm arc. I really like 10.5 pencil stuff and pencil barrel profile in general so a 6mm arc pencil barrel has the potential maybe to offer the highest BC and energy at range for a 10.5 pencil, maybe. It will be cool at any rate :-). Of course nobody makes a 10.5 pencil 6mm arc yet, heck maybe they never will. That leaves us with making a barrel from scratch, buy blank, extension, chambering reamer, headspace gauge. Or...hmm the Faxon 14.5 barrels use the same gas port location as the 10.5 barrels, hmmmm 🙂 🙂 🙂 . Faxon is 1:8 which there is some controversy about if that is "enough" but I am enough of a faxon Fanboi to trust them to have done their homework :-). So I grabbed a Faxon 14.5 from Brownells and a Brownells brand BCG. This is in line behind the 308 18" pencil project but I will probably go on lining up parts.

Sure you do :-). It just depends on the problems we have been forced to solve and the resources we had/have to solve them :-).

When you need to do something there is always a way :-). That could all be made out of wood dowels actually and it would still do the job, maybe not the .001" but def good enough to work :-).

Ok needed to measure exactly where the gas port needs to be with a white oak rifle minus 1" gas tube. made this jig here.....allows putting the BCG end of the gas tube right in the center of the cutout in the upper. They sell this tubing at most hardware stores, it is a Hillman product, not too expensive. Lathe turned this up so that it clamps up like a barrel extension. The answer I got was 1.221" closer to the receiver than a rifle gas 18" faxon pencil barrel. That all makes sense because it is a White oak AR15 rifle length gas tube minus 1", which amounts to Armalite AR10 rifle length gas tube minus 1.25" :-).

After a few hours of wrestling we would worry about cleanup hehe.

Lots of race car parts are magnesium, and you can TIG weld them, but you have to be careful to not let the part get too hot. I think once you have a fire hot enough to let a large mag part actually burn, the mag is not your issue ;-). Bill

The other factors in the NRA highpower stuff, and especially what they used to call the "Spring DCM"(DCM was what CMP was called for many decades) at camp Perry is the wind and the weather. I would guess 80% of my 600 yard service rifle slow fire strings were in the pouring rain and with a M1 Garand :-). The wind out on the edge of lake Erie can be interesting too :-).

For even more fun try some NRA service rifle :-). That teaches offhand, sitting, and prone both slow and rapid fire with a magazine change :-). I started out Jr smallbore indoor with iron sights then graduated to service rifle and or match rifle outdoors. The sitting and prone are assumed from the standing position. 10 shots in 60 seconds or so. Smallbore was the only discipline that taught kneeling kneeling is a really good field position, and the guys with prior military training said it is one of the best to get into from a dead run :-).

One thing that comes up a LOT, is where does the gas tube land inside the upper ?? Worth looking at that and addressing any potential issue. Might be your combination is perfect :-). I really like Aero stuff :-).

I think if you try the imperial sizing die wax you will not get those dimples. Lanolin from the drug store will work nearly as good if not as good.

I know they will make custom factory crimp dies. What some folks do is take a case, trim .100 off the end, then send that to them as the sample case. The end result is a "sideways crimp". Works good for cases that headspace on mouth. This is one I made up for 350 legend. I narrowed the crimp width too.

All of the 1:7 barrel blanks are "gimme your wallet, 4 pints of blood, the title to your car" hehe. Green Mountain might get on the 1:7 game some day. I would think Faxon tests stuff tho :-).

I see Brownells listed some faxon 6mm arc. But only heavy profile. I want a 10.5 pencil :-). The faxon are 1:8 by the look of it.

I'm always about being a cheap asterisk hehe, and learning stuff while I am at it ;-).

The wifi signal 800 yards would be the issue, there are antenna avail, even folks making home brewed ones that people use to plug into public wifi from miles away tho. I have set the software up that he is talking about, it is pretty simple overall.

For sure, it might slip right in, and the EMS folks will never believe it was an accident. There are only two sound reasons for running a long barrel, it adds enough velocity to be worth the weight, or you must run iron sights and it gives you a longer sight radius, but a bloop tube will do that too ;-). Bill

Lots of internet folks feel that people who say the 105 AMAX works for them in a 1:10 actually do not have a 1:10 :-). I can hook you with a few 105 AMAX, they are coated with something called "Danzac"...which is a kind of moly spin off product, Titanium Disulfide maybe :-). Does not look like Green Mountian makes anything tighter than a 1:9. Shame really, their product seems good and the price is good, and lots of stuff is "in stock:. Bill

105 AMAX will fit, they are a sort of stubby bullet for weight, and in a 26" barrel could hit 3126 fps, but my 1:10 rifling twist will probably not stabilize them. QL says 2847 in an 18". Apparently the 105 AMAX I have are collectors items :-). .500 BC, they were one of the first polymer tip 6mm heavies as I recall. They are not nearly as explosive as vmax.

Fire formed cases hold 57.0 grains of water maximum case capacity overflow which is what QuickLoad shows for 243AI.

Ok adjusted the headspace issue. and where this was all leading, or the next step was... Will 5 dummy rounds made from fire formed and resized cases feed from a Pmag working the bolt by hand ?? The answer is............yep like butter. These are 75 VMAX, fore formed with a maximum 243 load of superperformance.

Growing up as a teenage kid I worked ballistic tables from the back of the bullet makers books, I worshiped at the alter of ballistic coefficient :-). I would hope the VMAX stay around, or a bullet as equally high BC and explosive on small critters :-). The composition of the polymer tip should not make/break the explosive potential we would hope :-).

Absolutely, yes. The OD typically is not exactly concentric to the bore unless you turn it concentric. Indicator up in the hole is the best way IMHO. I have reworked a few factory 700 remington barrels where nothing ran true to anything else, when you got the bore dialed in all the other features were wobbling all over the place :-). Bill