Thread: 6mm ARC

Just waiting for the Barreled Action to arrive

Originally Posted by Sidetrack

Seriously though, there has never been a better time for the new, junior, light framed shooters or anybody needing to downsize due to injury/age related issues. The highly efficient 22/6mm cartridges available now, capable of utilising a good range of bullet weights and types, would see you in good stead for the rest of your shooting life. All wrapped up in a light to medium weight package means that they pretty much cover most general hunting scenarios without sacrificing terminal performance. In most situations, you’d never feel the need to gun up.
Yes, I know it’s sacrilegious but It’s not hard to envisage a “one gun does it all” situation.

Yup defiantly agree. Also think people are realizing that these smaller cartridges are cheaper to run and that you don't also have to kill the hill behind what ever you are shooting at.

Suppressors and limbsaver did that ,suitable for youth,slended built,recoil sensitive....without changing cartridge lol

Yes but then if you apply those to an arc or grendel you get an even softer shooting deer capable round.

My Howa barreled action arrived yesterday and I spent a bit of time setting it up .

Put it into a standard Houge stock ( if I end up liking the 6mm ARC I’ll probably upgrade to Carbon) , I had to spend some time sanding out the barrel channel because it was touching on the left hand side . I also had to do a little bit of relieving around the bottom metal so that the aftermarket hinged floorplate metal would fit correctly.
I then installed a 1.5 lb trigger spring which I had laying around from a previous Howa project.
Next was to mount a scope , in my box of bits I have a selection of Howa mounts / rings etc so after a dig around I came up with some Talley rings , but after a test fit I struck a problem of the screws being to long and protruding down into the action stopping the bolt from being inserted. I could have just ground the screws shorter, but couldn’t be bothered at the moment.
So some Burris bases and Ken Farrel rings were called into action and everything mounted up perfectly with my old faithful Meopta 3-9 scope .A larger bolt knob was installed and I’m ready for test firing tomorrow with some factory 108gr ammo before I start hand loading.

I thought I’d just give some initial thoughts on the Howa 6mm ARC .

This is my first Howa Mini , but have owned a number of the SA Howa 1500’s over the years .

I really like the compact action size of the Mini and that combined with the 20 inch barrel makes for a very short handy dimensioned Rifle , which is ideal for the Ute and SxS .

The varmint barrel isn’t really a varmint in my opinion, I’d rate it as a heavy standard size which isn’t a bad thing in my view because you get a little more meat in the barrel without it weighing a ton .

The action is typical new Howa and is far from smooth , but I’m sure it will smooth out as time goes by , just like all my other ones have .

I installed a metal aftermarket hinged floorplate magazine instead of the factory plastic box mag and feeding has so far been flawless for the first couple of boxes of ammo .

I have only shot the Factory 108gr ammo and I don’t know if it’s the Rifle or the Ammo but a number of times I’ve experienced a heavy bolt lift . The primers don’t look to bad and there are no extractor marks on the case head , but if I had experience that heavy bolt lift with my handloads I would have been backing of the powder charge a bit .
Initially I thought it might have had something to do with the hot temperature that I was shooting in yesterday here in Central Queensland ( don’t know how hot , but it was “ Hot “ even for here ) but I experienced a few heavy bolt lifts again this morning in the nice cool temperature at 6:00am .
The accuracy however is very good for a cheap brand new rifle with factory ammo .
So far I’ve shot 10 x 3 shot groups ( 3 shot groups because the mag holds that many and the barrel was heating up big time in the hot conditions ) and the average for those 10 groups is 21.8mm .
So the rifle straight out of box is shooting below an inch with factory ammo and that makes me happy because there’s a good chance I will be able to better that with handloads .

Before I shot the rifle I obviously cleaned the barrel and I noticed that it didn’t feel very smooth while running some patches down the tube . Maybe I’m spoilt with some of my other rifles , but it was noticeably rough and catchy .
I shot 5 rounds to get it on paper and then cleaned it with Bore Tech Carbon and Copper cleaners and used a nylon brush and patches.
The barrel was really fouled for just 5 shots and took some cleaning to get it sorted.
I shot 15 more rounds and cleaned again. Same deal it was very fouled and took some serious elbow grease to get it clean .
Another 15 rounds , same thing again but maybe not quite as bad .
I think the rifling and bore of this barrel are rough and not of great quality, but it’s a cheap rifle and it looks like it will shoot , so I’m not complaining.

Im not going to chronograph any shots just yet , because of the rough barrel I have a feeling that it will speed up anyway as it smooths out a bit after having a decent amount of bullets down the tube .

So as it is at the moment it’s all sighted in with the 108’s and I’m just going to shoot and enjoy it while I burn up the factory ammo .

So far I’m pleased I got it

Do yourself a favour & replace your nylon brush with a bronze one

I supplied a Howa 6ARC to a good customer & he commented about heavy bolt lift as well with factory ammo....

I didn't notice it when I shot half a dozen or so setting the scope up for him

Originally Posted by Kiwi Greg

I supplied a Howa 6ARC to a good customer & he commented about heavy bolt lift as well with factory ammo....

I didn't notice it when I shot half a dozen or so setting the scope up for him

That’s interesting to hear about the bolt lift .
Maybe the ammo is loaded a bit “ Hot “ or the Howa’s are maybe chambered dimensionally / throated in way that creates pressure ?
Do you think a rough bore / rifling etc could create pressure ?

Originally Posted by Ground Control

That’s interesting to hear about the bolt lift .
Maybe the ammo is loaded a bit “ Hot “ or the Howa’s are maybe chambered dimensionally / throated in way that creates pressure ?
Do you think a rough bore / rifling etc could create pressure ?

I haven't "seen it for myself" so I'm not sure, it could possibly a mechanical issue with a new rifle

It would be strange if it is an over pressure situation with a bolt action given it can be used in an AR

Originally Posted by Kiwi Greg

I haven't "seen it for myself" so I'm not sure, it could possibly a mechanical issue with a new rifle

It would be strange if it is an over pressure situation with a bolt action given it can be used in an AR

That’s a good point, and the two things that I usually look for in regards to pressure - Primers and extractor marks both don’t seem to be an issue so who knows what’s going on .

Projectile jammed on the lands maybe?
I had a 6.5 prc that when loaded jammed it was a good 100fps faster. Still accurate but would throw the odd flier

Maybe give the bore a polish with some JB bore paste?

Chamber clean of lube? Factory rust preventative on a new rifle

Lube in the chamber presents as pressure

I’ve shot 3 boxes of the Factory 108’s through the Rifle now and will start to reload those 60 cases ( keeping the final box as a control group , with its known performance from the first 60 rounds )
After establishing the distance to the lands I have made up 3 Dummy rounds using the 3 different projectiles that I want to try first , each one seated to put the projectile 20thou off the lands .
Originally I thought I’d use the 90gr TGK Sierra , but as you can see from the photo the 90gr TGK has to be seated a long way into the case which really takes up case capacity .
This 6mm ARC has to produce velocities that exceed my 6x45 by a decent margin to make me want to keep it . So running it as “ Hot “ as I can is a major factor for me .
I will be loading a batch of each projectile to ascertain which combo gives the best accuracy/velocity results .
I just thought it was interesting to see the differences of how far each projectile protrudes into the case when seated 20thou off .

From left to right

90gr Sierra TGK - 87gr Hornady hpbt - 85gr Sierra hpbt