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.

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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.

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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.

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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 :thumbsup:

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!!

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So proper cleaning then:D

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.

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

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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.

Bloody odd this, 6.5's generally shoot bloody good regardless of what you throw in them, especially 6.5CM & 260. I've always found you are trying to improve on the 3 shot 0.75 MOA that they usually produce straight up.

Greetings again @Sidetrack,
You may know the standard test for bedding but just in case here it is. With the action snugged down in the stock hold the barrel and fore end with one hand and loosen the front action screw. You should not feel any movement between the barrel and fore end. Do the same thing with the rear screw and the tang and stock. Once again there should be no movement between the tang and stock. If you feel movement then strip the rifle and remove the mag well which is just a loose fit between the action and floor plate. Reassemble and test again. If there is movement with the mag well in and none with it out then the mag well is binding or is too big for its space. It is possible that the action is hung up somewhere in its recess on the underside of the action so make sure that there are no rough edges on the top of the well. You can test the rifle with the well out if you like. To me this is the most likely problem with a dud scope right behind. Action screws that are too long or crud in their holes are possible as well.
Best of luck, Grandpamac.

Loverly morning here so took some me time to catch on the 260 progress. Had already gone through the above checks, thanks GPM, and found nothing untoward so as it’s a perfect range day here, and before I toss the scope, ran 2 x 3 shot groups with some Hornady factory 129SST’s which I found in Invers last year.
They are a reasonably spicy load but like the Corelokts, about 6” high. To test the scope, I dropped 20 clicks and shot the next three. Tracked spot on and while the group is nothing to write home about, it’s consistent so will now crack on with load development.

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Make sure you haven't or aren't about to run out of windage clicks on your scope,had a bit of drama with my 260 a wee while back with a replacement scope and new rings,was doubting scope but worked out I had run out of windage via the Leupols site and was scattering rounds like yours l.Then found out the rings were not true by placing some straight pipe in them and comparing to barrel,well out!.Changed rings to true ones,recentered windagef,sighted in and all good,the faulty rings were Leupolds too.

Sing out if you need any brass i have enough now and can spare some.

It’s been awhile since last update but have not long got this rifle back from the gunsmith. A number of niggly issues had to be resolved before I got on with load development.
Inspecting the brass after the last range outing, I had noticed that the shoulder was showing quite pronounced marking. Quick look down the chamber showed some pretty average machining with the shoulder heavily grooved. Not exactly Trueflite’s best work I would imagine but I guess the odd one slips through occasionally and it was a few years ago now.

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Decided to have that tidied up, the feed issue sorted, barrel threaded for a suppressor, trigger adjusted, and a confirmation that the bedding was all good to go. This rifle was also destined to receive some decent optics, for my benefit as well, so lashed out on a Burris HD Signature E3 3-15x44. Even though it’s hardly high end, was damn near a $1000 more than I’d ever spent on scope!!! I think my butt’s finally stopped squeaking now:D
So, all systems go. Slotted it into a set of Talley lows I had, looks good, sits nicely on the rifle so happy as. Got it close to where I wanted it and nipped it up. Mounted the rifle a couple of three times to check fit and bugger!! too low, went to cycle the bolt and no, contacts the scope mid handle. That I could sort with a bit of minor grinding but the eye line is just too low. She’ll need a set of mediums and I’m back to parking it in the safe. I really should divorce the bitch but I still love her so I’ll continue to stroke her gently in the continued hope she’ll start cooperating and let me get the best out of her. Some long range shooting is calling and the weather is on the improve.

Don't discount 120-gr projos , some .260's and 6.5's love them and within their useage-range/conditions etc they absolutely flatten deer often expanding better than 140's . An early True-Flight job on one of my 6.5-rifles (many years back before it changed-hands ) was an utter crappy disaster , hopefully yours works-out ok

Thank you, my thoughts were tracking that way. I’m going to start with 129gn SST’s as I have plenty but was building up a stock of 120-123gn’s for the Grendal so will be good to be able to share across both platforms if it works out that way.

The gun gods finally shone their light on the Catlins and timing was perfect. Not a breath of wind and a stunning winter day. I’ve had my first reloads ready for months so set up in the paddock over the road and went at it. Ignore anything in the white, just the two in each target area.

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Lapua brass, BR2 primers, 2209 powder, and 129gn SST’s. Couldn’t get them seated anywhere near the lands so set the length to the mag as close as I felt comfortable and still able to feed nicely. Conservatively started at 40.5gns up to 42.5. A promising start, then she wandered off a bit before gathering her skirt and closing up again. Not too shabby if I say so myself!! A massive confidence boost as well.

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No pressure signs at all so guess I’ll keep upping the powder charge now till one of two things happen. Next ladder will be 43gns up to 44.5 but would appreciate any feedback before I load those up. Cheers all.

Greetings,
Glad to see that things are improving. You might want to chronograph that load before adding more powder. 42.7 is max in the Hodgdon data but with the 130 grain AB which is likely harder. You won't see any pressure signs until you have gone too far. Max velocity for a 24 inch barrel will be around 2,800 to 2,850 fps less 25 fps per inch less barrel length. More testing at 42.5 and perhaps 43 grains if your velocity is low would be worth considering. I think that chronographing is urgent as the Hodgdons data may be for an older and slower version of AR2209,
Regards Grandpamac.

Greetings,
Dug up some recent chronographed results with the 129 grain Interlock which is similar to the SST in hardness. They stopped at 42 grains of AR2209 giving 2,750 fps in an 20 inch barrel so 2,800 fps should be about right for your 22 inch, It shot really well.
GPM.

Thank you GPM, that’s the feedback I’m looking for. The ADI manual confirms your Hodgson data at 42.7gns max. It’s been awhile since loading so questioning where I got the 44.5 max figure from?? Maybe why I stopped at 42.5. It doesn’t feel as stout as the Hornady factory ammo but if those velocity figures standup then I’ll be more than happy sitting where it’s at. I want to push this rifle out as far as it can so definitely need to chrony it at first opportunity. As you suggested, the 129sst’s were a great place to start so very happy given that it really did not like both types of factory ammo I’ve run through it.
Next step at this stage is to run a five shot group to see if I got consistency at 42.5 and then leave it at that for the time being till I can test velocity.
I have some 123 and 140gn ELD-M’s which I would like to work up loads for and interested to see if the heavier 140’s will actually perform in the rifle. Thanks again.

Those 120gr Sierra's you got off me should shoot bloody well too, they did for me in 260 & 6.5CM. Best of luck...

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Originally Posted by Sidetrack

Thank you GPM, that’s the feedback I’m looking for. The ADI manual confirms your Hodgson data at 42.7gns max. It’s been awhile since loading so questioning where I got the 44.5 max figure from?? Maybe why I stopped at 42.5. It doesn’t feel as stout as the Hornady factory ammo but if those velocity figures standup then I’ll be more than happy sitting where it’s at. I want to push this rifle out as far as it can so definitely need to chrony it at first opportunity. As you suggested, the 129sst’s were a great place to start so very happy given that it really did not like both types of factory ammo I’ve run through it.
Next step at this stage is to run a five shot group to see if I got consistency at 42.5 and then leave it at that for the time being till I can test velocity.
I have some 123 and 140gn ELD-M’s which I would like to work up loads for and interested to see if the heavier 140’s will actually perform in the rifle. Thanks again.

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Greetings,
I had an interesting experience with 6.5mm projectiles. I was working up some loads for the 129 Nosler long Range Accubond in the 6.5-06 for a friend. The rifle had always produced less than book velocity for modern data and closer to the velocity for older data. I started with the 129 grain Interlock projectiles to get the rifle on target and an idea on velocity. Next I switched to the LRAB projectiles which produced an additional 100 fps of velocity and consequentially more pressure. The Hodgdon/ ADI data which is all produced by Hodgdon is for the 130 grain Nosler Accubond which will likely develop velocity and pressure closer to the 129 grain LRAB. There is another fly in the ointment. Around 2002 ADI increased the speed of AR2209 and the the data previously mentioned predates that. So on one hand you are using a softer projectile which will produce less pressure and velocity. On the other hand you are using a powder that is faster than that for which the data is developed. From my tests with my 6.5x55 and the 6.5-06 these two things may balance each other, only the chronograph will tell you. In my 6.5x55 switching from a tin of AR2209 packed in 2000 to a pottle purchased in 2019 raised velocity by almost 100 fps. A short learning curve for me.
Regards Grandpamac.
PS Nick Harvey listed 44.5 grains of AR2209 for the 125 grain in his 6th Edition and Hodgdon/ ADI listed 44.3 grains for the 125 grain Nosler partition.

Load 10 of the best and the worst and test those. See what you get.

I have Nick Harvey’s 6th edition as well. Interestingly, my Sierra manual has no load data for the 129/130 grainers either and they make a 130. At the time, I think I researched a lot of H4350 loads as a comparison and some of those were over 45grains.
The old 260 load threads on here from 10-12 years ago has a fair bit of variance, some quite a bit over book max. The old story, every rifle is different, always start low, and worth re hashing the same questions every so now and then as things are changing all the time.
Now that I’m getting some of the reloading basics sorted, I’m going to start playing around with different powders. W760 for the 270 and I think it’s worth running some AR2213sc with the 140’s. Fun times ahead.