Thread: Ultimate compact rifle & catrige - 6mmGT/22GT in howa mini action

Originally Posted by gimp

53 pages of the .223 being effectively demonstrated to be the most practical ultimate cartridge of any size, let alone compact.

Thats one way to look at it.

Another might be that there are around 780 posts in that thread of which 164 give or take were by one member (21% of total posts). Now he is clearly a very experienced hunter who knows where his gun shoots and knows the limitations of it. However, he is shooting in a farm situation at animals that allow him to take his time and pick his shots. Most are of smaller deer and not large heavy bodied animals. Almost all of the other deer shown are of a similar type.
After about page 15 there are only a few new posters to the thread with just the same old people reinforcing the same opinion in the echo chamber the thread has become.

The 223 is a very versatile cartridge that deserves a place in every one's gun rack. It is an excellent young person's first center fire. Used by experienced hunters who know its limitations and are happy to pass up on marginal shots it is fine.

However, as an all-round, one deer cartridge to rule them all it is not.

Hi @300CALMAN, Sorry I don't own the design so I am not sure if it is appropriate to give his stuff away. It was by a guy I met at the rifle range. Maybe he is on this forum?

Originally Posted by hey

Hi @300CALMAN, Sorry I don't own the design so I am not sure if it is appropriate to give his stuff away. It was by a guy I met at the rifle range. Maybe he is on this forum?

Cheers @hey maybe? There is a couple of designs floating around, just haven't come across one yet. Maybe they are on the forum?

Originally Posted by Stocky

I agree with tentman your in dangerous territory making engineering assumptions especially as you clearly dont grasp even half the concepts.

The BAT action uses a 4140 chromoly steel (around 655Mpa yield) portion at the front for the bolt lug recesses and the barrel threads. This is the area that takes almost all the load and is further supported by the 7075 heat treated aluminum sleeve (around 450Mpa yield). It is larger than the howa mini (made of some sort of stainless probably a 416r(around 650Mpa) by a significant portion and far stronger and takes magnum cartridges. You can see the aluminium is not much weaker and the 4140 yield i gave is as supplied it can be much stronger whereas the 416 has issues with impacts if hardened further. Also the lugs on the mini are tiny, a kimbers are noticeably larger to take 308 cases. The lugs of the remington 700s or BAT action are larger again.

Everything behind the ejection point can be almost any material i.e. how ar15s can be made with plastic upper receivers and the majority are aluminum as all the chamber forces are maintained with steel up front and the only serves assistive functions and only needs to cope with recoil forces. there are lots of aluminium actions nowadays, seekins, sauer, gunwerks, blaser to name a few

Bolt thrust increases significantly as bolt face cartridge diameter does. A 62kpsi case the diameter of a 223 and one the diameter of a 308 is not even close to the same when talking bolt thrust its 56% higher. Also case diameter is the main determining factor is bolt thrust not powder capacity. This can be seen in the 84M and 84L kimber action which share the same action design from the ejection port forward as the bolt face remains the same even though i can run a 280AI in one that holds equivalent powder to most short magnums.
Its even hypothesized that with minimal taper cases that the longer cases actually work better as they gain more grip with the sides of the case to help the brass hold some of the force reducing bolt thrust.

After all that I know Guys have built 6mmBR Howa minis and their wildcats but all are playing on the fine edge of things where an oily chamber cause cause a failure whereas normally it would just cause a sticky bolt as damaged brass. Most smiths wont do it in NZ.

Lastly why build a 6.5GT on a Howa action when its performance gains in short short barrels is minimal then its no longer compact and for less weight a 16 inch 6.5 creed in a kimber will outperform it easily without going custom.

Good explanation about the bat action, Stocky. I believe the counter force for the bolt thrust is called "friction effect", where the case direct the force to the chamber wall, as much as half of the total force? A long straight case has better friction force than short & tapered one. That is one reason the nickels plated case is no good.
For you all firearm experts here. Here is something I am always unclear. For a bolt gun, is the chamber pressure more important than bolt thrust, or other way around? Cause usually I only hear people talking about bolt thrust in none bolt action rifle, like contender, but in a bolt gun I hear more about chamber pressure? hence people will attach a strain gauge to measure it and determine if the load is safe. I am an engineer and I do believe in math and numbers. So if you think you are right it is best to provide some solid science.

Hmmmm, you just reinforce my pet prejudice, I'll happily trust engineering, but I never trust an engineers! Do some reading on hoop strength versus shear strength and you mjght start to gain some understanding.

You have a good idea with the cartridge but no idea with the vehicle to take it forward - tell me that shouldnt feed my prejudice towards engineers!

https://www.nzhuntingandshooting.co....rminator-5607/

Or get a fast twist 22-250

I think the issue is not only the small size of the bolt tenons but the diameter of the thread on the barrel and the thickness of the receiver where the barrel screw in.( I have a spare Howa mini barrel at work I can measure on Monday. Or we can ask wingman).
My understanding is that it is a bit the same problem when you starts to get stiff loads in 28 nosler into a tikka t3.
Not enough steel around the chamber (1” or 25.4mm thread tenon diameter) where a Remington 700 will handle it better with a 27mm tenon thread diameter ( same pitch in both cases at 16tpi, so same depth of thread).

@hey I have a 6GT and its my main match gun. won a few and placed in a few.

It kills wallabies and smaller critters well, wouldn't hesitate to use it on a fallow etc but I use match bullets and they are no bueno for the deer, just like the 69gr experience you have had in the 223.

Pros: Easy to load and find accurate nodes (designed around 2208 & 105gr), lots of data, short - but designed around the AICS SA length 2.8"

Cons: dies are expensive, brass is $3 a piece (might be more now) and no factory ammo available in NZ.

I recently built a fast .22 centerfire and settled on a 22-250AI as it is the same performance as the 22 CM but toyed with a 22GT as I have bushing dies. I ended up going with the 22-250AI because brass is cheap, I can use loaded factory 22-250 ammunition if I want and dies were easy to get & available in NZ.

Yes the .223 will do everything you want, Yes the .308 will do it better, Yes .270 is what god shoots...

But if YOU want a 22GT on a Howa Mini, fill ya F*ckn boots mate... You'll likely find the mag length of 58mm is a bit short for running long heavy for calibre bullets (the whole point of fast .22 centrefires) but give it a go!

Just make sure to start a thread with lots of pictures so we can all learn from your experience too please

Good luck

@Friwi, the barrel tennon on the Howa mini is 22mm dia.
I too would have exersized on the side of caution with using a howa mini due to unknown strength but Howa have just released their super light action in 6.5 creed and .308 win which is the same mini action only 6mm longer and a bit more material removed to fit a wider mag. Any apprehensions I did have about strength of these actions have gone.
The best donor would be the .450 bushmaster which already has the .470" bolt face and extractor to suit, the .450bm mag would also feed the GT case with no mods.
Or.. one of the new howa super lights in creed oe .308. They have a 3 round removable mag with a 2.8" internal length

Originally Posted by Got-ya

Thats one way to look at it.

Another might be that there are around 780 posts in that thread of which 164 give or take were by one member (21% of total posts). Now he is clearly a very experienced hunter who knows where his gun shoots and knows the limitations of it. However, he is shooting in a farm situation at animals that allow him to take his time and pick his shots. Most are of smaller deer and not large heavy bodied animals. Almost all of the other deer shown are of a similar type.
After about page 15 there are only a few new posters to the thread with just the same old people reinforcing the same opinion in the echo chamber the thread has become.

The 223 is a very versatile cartridge that deserves a place in every one's gun rack. It is an excellent young person's first center fire. Used by experienced hunters who know its limitations and are happy to pass up on marginal shots it is fine.

However, as an all-round, one deer cartridge to rule them all it is not.

He is also 74 years old and what you have read is only a snap shot of his most recent experiences with the .223, along with the addition of your assumptions. Gimp, is correct of course.

But as said a couple posts back "if YOU want a 22GT on a Howa Mini, fill ya F*ckn boots mate..."

@Wingman, it took you a while to reply to that one ;-)

Originally Posted by Friwi

@Wingman, it took you a while to reply to that one ;-)

Ha.. I've been busy... and your didn't put the @ in front of my name so didn't get the mention notification..

I reckon a 6mmGT would be an a sweet candidate for a lightweight compact rifle. Its a very efficient and easy to tune cartridge with minimal recoil.

I would however build it on a standard length action to suit 108gr ELD's

have 1500 rounds with the GT on my comp rig, will keep the hagged brass at the end of its life for a hunting rifle one day