Where to start.

I am seriously looking at a 6x45. Because I have a use for one, shooting small deer out to 200yards. There are no restrictions in New Zealand on size calibers vs animal size.

Currently I use a T3 223 with 1:12 twist and 55gn pills for this job. No issues there, been doing it for years. My current barrel is 16". I can get 3000fps with handloaded 55gn pills from this set-up.

The 6x45 has me interested. I see a benefit being I could load up to 80gn pill in it for one.

Which got me thinking. Now-a-days you can get fast twist barrels for the 223, 1:8, 1:7 that type of thing.

So, wouldn't I be better off just rebarreling my T3 to a 1:8 or 1:7 twist barrel and using heavier pill in the 223 range that have better ballistic coefficients than their 6mm counterparts?

Are there other benefits of going to 6mm in my 223 I am not seeing?

Thoughts please? I am not interested in other 6mm variants only the 6x45 as it is a straightish conversion. My current 223 is suppressed, the 6x45 will be also.

6.5 Grendel / 264 LBC.

The 6mm has a little more surface area for the gas pressure to push, and a little more perimeter to make friction. I think for the same bullet weight you can get a little more velocity for an equal length barrel, all things being equal. I shoot a 6x45mm with a barrel twist of 1:9.5", normally use an 85-grain bullet (I have some other ones, 55 and 70 grain, but somehow don't get around to using them).

Yes a rebarrel is all you need except for dies. Being the 6x45 is a necked up 223 the rest of the parts in the rifle are the same.

I had a 6.5 Grendel and got rid of it. For it you need all the parts of the rifle to be changed. Brass is expensive unless you fire form 7.62x39.

Les Baer makes a 6x45 and the two rifling twists he uses is 8 and 9. I have a 9 twist and it even shoots the 100 grain bullets just fine. I build mine it's not a Les Baer rifle.

If it aint broke why fix it?

You can use a 10" twist or 12 " twist and use bullets heavier than the 223 will push.
It will probably be more accurate and the 75 to 100 grain bullets will certainly penetrate better.

I have two 6X47 rifles using the .222 Rem Mag case. For most use on critters bigger than prairie dogs the 6mm is much better.

To my mind a cartridge needs an appropriately sized action. I have long bought that the little mini mauser action Brno / cz in 6x45 would make a wonderful lightweight small deer stalking rifle. But in th uk we do have velocity / muzzle energy requirements and its not quite there in terms of velocity with 100 gn bullets (min bullet weight in Scotland for all deer save for Roe) to meet min muzzle energy requirements.

With a T3 sized rifle if you want a 6mm go straight to the 243 win - works all day long and ammo every where, but fully appreciate there is no fun in getting something straight off the shelf.

I shoot the 6X47 Rem as well and am thinking of doing a 6X204 Ruger just because .204 Ruger brass is much easier to find. I run a 20" barrel and push 70 grain Nosler BT to 3100 fps pretty easily.

I would recommend a 1:10 or faster twist for the 6X45. My 6X47 uses a 1:12 twist and it only likes bullets around 75 grains or less. I've tried up to 85 grains but my groups just open up once I go over 75 grains.

However a faster twist .223 might just be the ticket as well. I'd probably just go with what I got the best deal on a barrel with. If you go with a .223 I'd probably go with a better constructed bullet like a Barnes TSX or the new Nosler bonded core or Partition in .224 caliber.

Having wreslted with the same issue, I built a 6x47- because I had the reamer and dies, otherwise I would have went 6x45

I have both, but the 6x45 has been my favorite since about 1980..I have used the GS Customs 75 gr.HV HP on deer and antelope and I have culled Springbok, Impala, and Kudu with it..It is a great killer up to 200 yards or so with heart/lung shots and of course head and neck shots..

I load H4198, H322, and H335. I have also used the old 75 gr. Barnes (discontinued) but still might be a few boxes around. My favorite varmint load is the 25 grs of H322 and the 60 gr. Sierra HP match bullet. I have a 1x10 twist.

If I had to choose only one small caliber rifle it would be the 6x45. It is better in the wind and we have to deal with that in Idaho, and its better on coyotes and pigs than my 222 or 223.

My next choice up would be the 250-3000, another caliber I really am fond of.

quote:

Originally posted by Atkinson:
I have both, but the 6x45 has been my favorite since about 1980..I have used the GS Customs 75 gr.HV HP on deer and antelope and I have culled Springbok, Impala, and Kudu with it..It is a great killer up to 200 yards or so with heart/lung shots and of course head and neck shots..

I load H4198, H322, and H335. I have also used the old 75 gr. Barnes (discontinued) but still might be a few boxes around. My favorite varmint load is the 25 grs of H322 and the 60 gr. Sierra HP match bullet. I have a 1x10 twist.

If I had to choose only one small caliber rifle it would be the 6x45. It is better in the wind and we have to deal with that in Idaho, and its better on coyotes and pigs than my 222 or 223.

My next choice up would be the 250-3000, another caliber I really am fond of.

Someone over on AR15.com a while back was making 25x45's. I wasn't interested so didn't read much into it.

Like I said my 6x45 barrel has a 9 twist and it will shoot the 100 grain Hornady roundnose into .250 inch easy. That's a fairly long bullet and it stabilizes is just fine. I also have a cast bullet mold for it in the seventy grain range and got a load that pushes it to 2600 into small holes. Nice for varmints.

quote:

Originally posted by SmokinJ:]

Someone over on AR15.com a while back was making 25x45's.

When I was getting the 24V rebored, the gunsmith asked what if it didn't work. Answer, do it again, this time for 7mm instead of 6mm. No biggie, but didn't think of 25x45, my bad.

I have mini mausers in both calibers.....I've used the 6 X 45 on whitetails and had DRT results with.....believe it or not.....Hornady 70 gr sx bullets.

To date it's the largest bullet I have used in the 6 X 45 and wouldn't hesitate to use it for pronghorns but would take my 6mm Rem first as the ranges can be long.

IMO the 6 X 45 has a small edge over the .223 for (even small) deer.

If you're going to use a mini Mauser PM me and I might be able to assist you with a barrel.

Okay, final question then as I am going to do this in 6x45.

Barrel length?

My current 223 T3 has a 16" tube. With a ASE-jet Z CQB can on it it adds another 120mm. So it is still nice and handy.

I get 3000fps out of 55gn handloads (26.5gn BM2)

I was thinking 18" max for 6x45. According to the ASE webpage compatibility chart I could fit my same can to a 243 cal rifle. Happy with that! Another option could be a Sonic 45 can, which only adds 120mm extra also and I can remove some baffles with that can too (which I may do as it is made for a 243 which has a heck of a lot more powder than the 6x45).

Will prob go a 1:10 twist.

Thoughts on barrel length?

I forgot to add my 6x45 has an 18 inch barrel, its on a L-461 old Sako action, with a custom stock done in English styling..It weighs 5.3 lbs and I recently shot a 10 shot group that measured .265 and have done this on half a dozen ocassions over the years, but always under .500..not bad for a slinder light weight rifle.

I shot my last whitetail with the 70 gr. Nosler balistic tip by mistake. Loaded the wrong bullets in it..The buck was running broadside at about 100 yards and I hit him in the shoulder and he ran another 75 yards and fell dead..had a nickle size exit hole and left a fairly good blood trail..I would not have thought that bullet to perform that well, as I always use GS Custom 75 gr. bullets and still recommend them for deer size animals.

quote:

Barrel length?

20"....it works well for me.

quote:

Originally posted by vapodog:

quote:

Barrel length?

20"....it works well for me.

+1

20" as well for my 6X47.

I have mini MK X in both also, 20" barrels on both. 64 grn win bullets in the .223 and 80 grn rem in the 6 mm. To be honest, I really cant tell the differance on deer at the 150 yds or less they are used at.