View Full Version : It came in. 6x45mm upper.

06-30-2011, 7:10 AM

There's a set of 3 DMR's. 2 x 5.56 and 1x 6x45mm. I went ahead and sized up 50 cases and got them primed. I'll drop powder and projectiles tonight.

Now I have to figure out a way to mark the cases so I can't ever mix between the 2. I tested on a dummy round last night and if I try to set one in a 5.56 gun the bullet could possibly set back in the case far enough for the bolt to close far enough that someone might miss it or bang it in and that would cause ugly things to happen. So, I'm thinking of red staining all the 6mm cases on the case head. At least then I'll have an indicator.

So, anyone else here a 6x45 fan?

Right now I'm loading 70gn Speer TNT's and 80gn Winchester sp's in it. Later on I'll get some more interesting bullets... probably darned barnes TTSX or DPX.

Anyway, all 3 run 25 or 30 MOA in either the rings or bases. 2 are 4-16x scopes (bushnell banner, bsa sweet .223) and one is a bushnell elite tac 10x. I put the magpul grip on the 6mm and wow that's a lot more comfy. Anyway, nothing mall ninja'y but good fun rifles.

The new 6mm has a crowned 18" BHW stainless match barrel. The other 2 have 16" BHW blackened stainless M4 profile barrels.

06-30-2011, 8:19 AM

06-30-2011, 12:02 PM
Very nice and simple. A fresh change from what we usually see around here.

Also, take a look at the Hornady GMX 80 gn. bullets(lead free, I remember you saying something about hunting). You may like those for the 6mm.

07-08-2011, 5:57 AM
Ok. I have Remington 80gr soft points and 70gr speer TNT's. IMR 4895 and Varget. I couldn't find any CCI 450 primers so I'm stuck with 400's which means staying down away from max loads, which is fine.

So, how about some help with the varget load data. I sent a message to Hodgdon's help line but haven't heard back. There's .223 data on the can which I figure I could use if I drop the referenced bullet weight by 10 grains and then do the usual start low and work up bit.

I4895 data was easier to find. I've got a few test rounds rolled up with that powder already. May try them out this weekend.

07-08-2011, 6:28 AM
These do less than half MOA in my custom Shilen AR in 6x45, I have a bolt gun as well (R&D Precision) but the load is 1 grn higher. You don't have to bother going to extruded powders like Varget, 4895, or RL15, the 748 and H335 ball gets the job done.. unless you are real anal and want .25" of less, to me .5 is more an enough.. but it's just me.. ;)

6mm223= 26grn of 748 70grn SMK
6mm223= 26grn of H335 70grn TNT

70gr bullets is your typical max, depending on your rifle twist, anything heavier will open up the groups, for instance neither of my guns like 80grn or 87grn (1.5"-2"), TNT is OK, I like the MSK better as the Boat tail seats better for the me.

07-08-2011, 7:15 AM
Awesome tip. Grazi.

07-08-2011, 7:22 AM
I actually like the round but the problem is no major manufacturers build the barrel.

07-08-2011, 8:58 AM
Kind of a different beast, but I have a 6x47/222 Rem Mag chambered Encore and have done well with the Sierra 70 grain BTHP MK and the Hornady 87 grain VMax - Grafs carries a pretty good selection of 6mm bullets and is doing a sale on their Hornady 58 grain VMax.

07-08-2011, 8:29 PM
I actually like the round but the problem is no major manufacturers build the barrel.

Actually, this caliber is making a comeback. there are quite a few barrel makers for it, I bought mine when it was not as popular a few years ago (even though the round has been around since the 1960's) my barrel alone was $600 but it's also a Shilen... I've see 6x45 barrels in the $300 range which is actually not bad at all. In my opinion, this is an awesome round, 30% more power, 150 yards more effective, and better BC in choice of bullets, the down side of course is you really cant get bulk in bullets like the 55 or 62 gr 224...

07-08-2011, 8:58 PM
You get the higher BC 6mms but you can't get much velocity with the .223 case.

Good on ya for doing something different.

07-11-2011, 7:13 AM
You get the higher BC 6mms but you can't get much velocity with the .223 case.

Good on ya for doing something different.

I dis-agree, because the dia of the 6mm opens up the 223 case mouth, you can add more powder thus the following:
Base on similar bullet weights if you compare
69gr 223 2900fps
70gr 6x45 3100fps

Ideally for accuracy, the magic number is 2600-2700 fps for most calibers... in the 223 it's 2750fps, the 6mmx45 is 2900fps

07-11-2011, 10:50 AM
I dis-agree, because the dia of the 6mm opens up the 223 case mouth, you can add more powder

No. You're only opening the case neck, where there isn't any powder. Ackleyizing a .223 would get more velocity.

The bigger (105/107) 6mm bullets shine at 2,900 and above, the 70/80 range really like 3,100.
Most 6BR guys who use the light bullets are using a 12 or 14 twist, which could be why you're not getting tight groups with them.

Hey, you bought it, you like it. No need to convince anyone else.

07-11-2011, 2:24 PM

07-12-2011, 7:37 AM
No. You're only opening the case neck, where there isn't any powder.

Ahhh.. think about it, when you open the neck up, you made more room volume in the case for more powder (that extra 2-3 gr of powder (H335) adds 200-300 fps).

07-12-2011, 9:02 AM
Ahhh.. think about it, when you open the neck up, you made more room volume in the case for more powder (that extra 2-3 gr of powder (H335) adds 200-300 fps).

But then you're stuffing a bullet into that neck so whatever space was created is occupied with bullet, not powder. If you open up to even 30 caliber and fill the neck with bullet you still don't gain anything. Maybe (only maybe) there's a slight change of the shoulder angle but I would think that amounts to nothing.

07-12-2011, 9:51 AM
Took it out over the weekend. I was able to hit baseball size targets at 400yrds. Smoked a chipmunk with it.

Accuracy from the sample loads I did up is good. The higher end charges were the best. I didn't get near max, nor did I find "the" load for it. I'll do a little more development. I'm starting on some varget loads later today. I didn't see any signs of high pressure so I think I'm going to shoot for as fast a load as I can get with .5" groups or better since I'm so close to a full case. I lucked out with the .223 recipes and found one that makes ragged one-hole groups right out of the gate.

Note, TNT 70gr have to seat pretty deep in the case. The 80gr Remington PSP's don't have to seat nearly as deep. I'm not sure if I like the TNT's yet.

07-12-2011, 9:56 AM
So what does a 6x45 clock with 80gr loads? 2700 fps or so?

07-12-2011, 1:30 PM
So what does a 6x45 clock with 80gr loads? 2700 fps or so?

Actually max is around 2900fps, possibly more in a bolt gun.

I know in regards to opening up the neck, some member think you don't gain that much more powder but when you are loading this caliber, .5 grn of powder can equate to 100fps, but nuff on the argument of powder gain or not, 6mm223 is a great round, I own two as well as a number of 223.

07-12-2011, 2:21 PM
Load data I'm looking at (which is extremely limited and 2nd hand) shows 80gr getting 2800 - 2900. Regardless, with 6x45 I'm relying on accuracy more than devastating power anyway so I'm not looking for high velocities for the kinetic energy so much as for the flatter trajectory.

I'm gunna have to get a chronograph at some point though.

07-12-2011, 2:32 PM
One wildcat for people to consider is 6*42 which is a necked down 6.8 SPC case. It is wider so it has a larger case capacity than 6*45 but it is also a shorter case so long bullets are held nicely.

I think it's designed for 90-105 grain bullets with velocity near 2,900 fps if I remember correctly.

The only down side I can think of is that it needs 6.8 SPC magazines.

07-12-2011, 4:31 PM
If you're looking for a 6mm - take a look at Robert Whitley's 6ARturbo40.
Pushes 105VLDs at 2,950 with 30.60gr of Varget.
Only need 11moa of elevation at 600yds, 26moa at 1,000yds Supersonic to 1,350.
Only difference between it and a 6BR is the .445" casehead vs the BR's .473".

Left: .223 w/69gr.......Center: 6.5Grendel case......Right:6ARturbo40 w/105VLD (6.5G case necked-down to 6mm and fire-formed, )

gun toting monkeyboy
07-12-2011, 4:44 PM
I always wanted one of those. Ever since I read about them in COTW back in college. It looks like a cool concept. But one more cartridge to load for my AR platforms sounds like a bad idea for me personally. I am the type of idiot who would grab one gun, and several boxes of the wrong ammo, and drive a few hours to go shoot. And then find out once I am there that I am SOL.

07-12-2011, 4:52 PM
The advantage of the 6x45 is it uses the plentiful 223 brass cases and 6mm bullets, going to other 6mm platform defeats the purpose, if you need to go there and cost is not an issue, then the 6.5 Grendel is also a great choice as well as others have mentioned... if you go AR10 style you have 243, 260, and 308 calibers

07-12-2011, 6:00 PM
The nice thing about the 6*42 is that you don't have to do fire forming and it can use bullets with a higher B.C. than anything you can load in a Grendle and still get high muzzle velocity. It's the flattest and has the least wind drift AR wildcat I know of that uses ~common brass, magazines and bolts in an AR.

07-12-2011, 11:22 PM
nice! first time i think ive heard of that round in an AR lately..

07-13-2011, 9:34 AM
I was an inch from getting the 6.5 to begin with but I wanted to stay with the .223 case. My next upper though will probably be something in a larger cased 6mm... I like what I see in the 6mmBRX. It'll have more recoil than I want but it'll be super fun for playing at very long ranges.

07-13-2011, 11:58 AM
The problem is with chambering (BRX). Very difficult to make an AR15 bolt work with a .473" (AR10) boltface. Just not enough metal around the barrel extension.

The 6.5Grendel was based on the 6PPC which shares the .445" boltface/casehead dimension (and happens to be the most accurate chambering ever developed). Whitley's first iteration (6mmAR) was just the 6.5G necked down to 6mm. The second (Turbo) was pushing the shoulder forward .100". The last (Turbo40) then added changing the shoulder angle to 40 as is used by the 6Dasher and 6BRX.

Gotta love 6mms in ARs. Best of two worlds.

07-13-2011, 1:23 PM
yeah, after looking at the options it looks like turbo 40 is the only decent option. I don't mind handloading but I don't want to have to cut rims down which appears to be the best route for the brx. That's not as much fun. Thankfully I'm about a year away from that. I've got my 6mil for now.

07-13-2011, 4:31 PM
Yeah, Whitley says he still sells a number of the straight 6mmARs because some folks fear fireforming.
My Turbo40 was only the 243rd 6mm he's made, not a lot of them around.
One funny part of the cut-down rims for the BRX is that some will have feeding problems because there's not enough caserim to catch.
I'm sure Bill is working on it. I know they did have Kiff work up a different reamer just for ARs.