Thread: Breaking in the 260rem and load development

When I started down the path to reloading, and my initial post on the load development of the 270, I decided to take the 260 (REM. Mod700 SA, 22” Truflite match barrel, 1:8.5” twist, in a HS Precision stock) to the range at the same time, mainly to continue the barrel break in process but also to settle myself in at 100m before cranking up the big gun.

I had photographed the initial five rounds to get it on paper (which I can’t track down now) at 75m and the group was looking very promising but rounds five to ten showed around a six inch vertical spread. I’m using factory Remington 140gn Corelokt.



Checked the barrel back at home and was looking pretty crudded up so gave it a careful clean and the next range session gave me these results. About 2 1/4” horizontal spread. First two touching then it started to wander off.



Not expecting too much at this stage re accuracy but the process is definitely showing some interesting results. Gave the barrel another clean so will see if anything changes again on the next five that I have left. Not sure where I’ll go with it next but if it seems to have settled down will probably attack load development after sorting the 223.

Has your stock been beded?
Also what are you planning to load in the .260

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Look at the bedding of the rifle as mentioned above.

And make sure the mag box is not binding

Ok, some background detail. This rifle has been languishing in the safe for a number of years. It started life as a .308 action with an HS Precision stock and bottom metal that I bought off TM, very cheaply I might add. Back when I had atrocious work/life balance, I toyed with the idea of a short action, light weight hunting rifle. Lord knows why but anyway, off to Truflite it went for a barrel chambered in .260 and they also bedded the action for me. Had a nice older Bushnell Elite 4200 3-9x40, so fitted that on a set of Talleys. Then apart from the initial five rounds it has sat in my safe ever since.
It has become a prime example and lesson on why, whenever you go down the road of building a custom rifle, you should be very clear on what you are trying to achieve and how it is to be used. Outcome is paramount.
Don’t get me wrong, it’s a nice bit of kit but it’s not what I expected or hoped for. It’s not light, 8 1/2 pounds, the stock feels fat in my hands and it seems a bit nose heavy. It also won’t chamber rounds out of the mag so a bit of adjustment required there. For all that, it handles nice, recoil is minimal and holds steady off hand. So nothing that can’t be sorted. I’m going to persist with it as I still very much like to have a 6.5 in the closet and some of my prejudices arise from having handled a Rem. Mountain Rifle all these years which is a completely different animal in fit and feel.



For reloading I’ve collected the following:

Powder - AR2213sc
Cases - 100 x Lapua(new)
Projectiles - Hornady 129gn SST, Hornady 140gn ELD-M, Sierra 130gn GMK, and Nosler 130gn Accubonds.

As there is clear improvement, and before I go tearing everything down, have cleaned barrel again so next step is to fire the next five rounds off a bipod and bag, not the Stinger and see what shows up. Then we’ll go from there. It may just not like the Corelokts.

Find some superformace powder for it.

Looks like a nice bit if kit

The group you've posted looks like it starts great and then goes pear shaped, are you letting the barrel cool between shots? A lot of rifles wander like this when they get too hot.

I'd be checking ring screws are tight with a torque wrench as well as the action screws torqued to the manufacturers specs. Overtightened action screws are the devil.

After that I'd look at ammo and then technique. Are you shooting off a bipod or sandbags?

With the barrel cleaning, a couple of my past 308s shot like dog shit with a dirty barrel, my rem mag on the other hand shoots pretty good clean, outstanding dirty. Also when you say clean are you using solvent?

Barrel cleaning was with a patch soaked in Hoppes solvent run through a couple of three times, then ten run throughs with a bronze brush. Followed by another patch clean, and final wipe through with an oil patch then dry patched till clear.

Will recheck mount and action screws before I head out again. Just waiting for this Spring weather to settle a bit, but to be fair, I did head to the river on the good days chasing the wee wriggly things and mapping out the new bush blocks I’m hunting so do need to prioritise I suppose. Life is so full of choices LOL!!

As outdoorlad said get some Hodgdon superprofrmance and run 140 or 143 eldx they work awesome, in all the .260 i load for

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Originally Posted by Sidetrack

Barrel cleaning was with a patch soaked in Hoppes solvent run through a couple of three times, then ten run throughs with a bronze brush. Followed by another patch clean, and final wipe through with an oil patch then dry patched till clear.

Will recheck mount and action screws before I head out again. Just waiting for this Spring weather to settle a bit, but to be fair, I did head to the river on the good days chasing the wee wriggly things and mapping out the new bush blocks I’m hunting so do need to prioritise I suppose. Life is so full of choices LOL!!

So proper cleaning then

Sounds like time well spent and you're making the most of the weather which is awesome, I've been spending too much time at work ha ha

For what it's worth this is my suggestion steer clear of the 140 grain ammo you're a bit light on twist at 8.5 130g would be a better bet .

Try a faster powder like AR2209 or H4350.

Hi all. As in my 270 reloading thread, time to update progress. I did manage to slip down to the range and run another five rounds through. Last of the factory 140gn Corelokts and no surprises there. While the pattern is just as random, the barrel is clean as a whistle. No fouling, just a slight dulling. Have gone through the usual checks to look for anomalies but everything seems ok so time to start finding out what this baby likes.



An observation. Different coloured (brass and silver) primers in the box???



There’s a lot of love out there for Superformance and the 143 ELD-Xs, neither of which I have at the moment, so will go with what I have on hand and my random choice is the 140 ELD-Ms using AR2213sc (other powders in stock are 2209, 2206h, and W760). New Lapua brass and BR2 primers.
Haven’t sorted my start loads yet so will report in when I’ve done my home work.
Cheers all and thank you for the feedback.

Greetings @Sidetrack,
Something is seriously wrong with the rifle to shoot that badly, most likely the action binding on the mag box or other serious bedding problem. Did you fire it with the .308 barrel and if so how did it shoot? You may have discovered the reason why it was so cheap. In any case the problem needs to be found and corrected before any more ammo is wasted. Another option is that the scope is stuffed. If the bedding checks out OK try replacing the scope with one that you have previously found to be accurate on another rifle. A bore sighting and two shots should give you an answer. Last did you buy the ammo new? If not it may be a collection of bullet weights. Once the bedding mag box has been corrected I would start with the 129 SST and AR2209 which shoot exceptionally well in my 6.5x55. Sort the bedding first.
Regards Grandpamac.

Thanks for your thoughts GPM. I’ve pulled this rifle apart and it slots back together nicely. No evidence of binding anywhere and seems to sit smooth and snug in the bedding. I bought it as an action only and was sent to Truflite for a barrel fit and bedding.
Ammunition was store bought factory box. My hope was that the rifle just didn’t like them and I would just try something else.
The scope is a secondhand purchase and your right, it should be looked at with some suspicion. A new purchase has been contemplated and I was reluctant to strip the scope from either the 270, which is under going load development in conjunction with this one and the 223, which I’m hunting with currently. I’m taking it to Stewart Is. in a couple of weeks time so when I’m back, that’ll be the one to use for testing.
The 129gn SST’s were actually my first choice, as I had 150 of them, and 2209 will give them a bit of pep so you’ve convinced me. I’ll start with those.
Thank you.