Instead of starting a new Thread about my 6x45 vs 6mmARC journey I thought I’d just post some things up here .
I own a 6x45 built on a Tikka action and it performs beautifully for it’s intended role of Varminter/small Pig Rifle using Sierra 85gr hpbt at 2865fps with H4895 powder .
The 6mm ARC interests me though because maybe it could be a 6x45 on steroids which would only be a good thing .
So I thought I’d just give some initial thoughts on the Howa 6mm ARC 20 inch Varmint barrel rifle I recently acquired.
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 Pickup and SxS .
The varmint barrel isn’t very big in diameter compared to other varmint barrels that I’ve seen and owned . 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 factory ammo ( more on that later )
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 ( don’t know how hot , but it was “ Hot “ ) 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 15 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 , I’m in Australia and it’s our summer ) and the average for those 10 groups is 21.8mm at 100m .
So the rifle straight out of box is shooting a fraction over 3/4 moa 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 .
Now a bit of an update on the heavy bolt lift .
I can eliminate pressure from the equation because I spent some time dry firing the rifle and maybe 1 in 5 times lifting the bolt to recock the action was a hard/heavy lift .
I disassembled the bolt and gave it a good clean with brake cleaner ( it was covered in a layer of some kind ) then very lightly oiled everything with an oily rag .
A visual inspection of the lugs etc isn’t showing anything out of the ordinary and after the bolt clean I think it is a bit better , not fixed entirely, but better .
So I’ll just keep an eye on things and see if it smooths out over time .
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
I’ll keep posting updates as I go and chronograph the velocities after I’ve got at least another 40-50 rounds down the barrel .
Ken
