AR10 Specific .260 Load Needed

[19Scout77]

I am in the process of building a .260 upper and need to supply some test ammo. I will be shooting 123 amax and 140 amax. Anybody care to hook me up with a recipe or two using those bullets and preferably 4350? I am looking for a middle of the road conservative load that will mag feed those bullets. This ammo is strictly for function testing the new upper--no need for anything fancy at this point.

Please provide all load specs. All cases will be virgin. TIA.

 

[BCP]

Re: AR10 Specific .260 Load Needed

There's a huge thread in the reloading depot with plenty of 260 loads, look there.

260REM brass
42.5 grns H4350
140 grn Hornady A-Max
CCI Benchrest primer
OAL 2.810

from first page of said thread

 

[19Scout77]

Re: AR10 Specific .260 Load Needed

BCP- While I appreciate your admonition and sorry if I some how inconvenienced you but nothing in the load you cited in any way references its use in an AR.

In fact, there are next to NO .260 AR loads in said thread

 

[snaglytooth]

Re: AR10 Specific .260 Load Needed

I have a gap built AR-10 260 and it likes.

140 Amax
40gn H4350
2.777 COAL
Federal 210m
Remington brass

Shoots really well.

I can load it hotter but it beats the shit out of my brass.

 

[sermonator]

Re: AR10 Specific .260 Load Needed

Since no two rifles ever shoot the same, you're going to have to start with some basic load data (starting low) and work up to see what shows promise. Because of the magazine, your seating depth options are limited. Variations are going to be charge, powder, primer and bullets. BUT the only way to get there is to load up a bunch of rounds and go shoot them.

 

[19Scout77]

Re: AR10 Specific .260 Load Needed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sermonator</div><div class="ubbcode-body">Since no two rifles ever shoot the same, you're going to have to start with some basic load data (starting low) and work up to see what shows promise. Because of the magazine, your seating depth options are limited. Variations are going to be charge, powder, primer and bullets. BUT the only way to get there is to load up a bunch of rounds and go shoot them. </div></div>

Did you actually read my original post? You have provided info relevant to a question that was not asked.

 

[19Scout77]

Re: AR10 Specific .260 Load Needed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SNAGLYTOOTH</div><div class="ubbcode-body">I have a gap built AR-10 260 and it likes.

140 Amax
40gn H4350
2.777 COAL
Federal 210m
Remington brass

Shoots really well.

I can load it hotter but it beats the shit out of my brass. </div></div>

Thanks. That's what I'm looking for.

How about 123s?

 

[k2peaker]

Re: AR10 Specific .260 Load Needed

I'm on the same path for a .260 AR10 (JP LRP, 22" barrel).

Here's what I've found thus far:
Test Load -- warning, <span style="text-decoration: underline">too hot</span>:
42.0gr. H4350
OAL: max mag length
139 gr. Scenars
Primer: CCI BR2
Velocity: 2680 fps

But, I'm still getting pressure signs -- extractor marks and an occasional pierced primer.
I'm going to back off another .2gr or .3gr. FWIW, I started higher than that (42.5gr) and was completely trashing brass (rims bowed).
I may also try some mil spec LR primers. I wanted to get at least 2650 fps but may have to fall below to reach acceptable pressures. I do have an adjustable gas block but haven't tweaked it yet. I shouldn't be too surprised relative to the 40 gr. H4350 posted since I'm quite a bit above that. I'm considerably below my bolt .260 charge but many differences account for that.

 

[k2peaker]

Re: AR10 Specific .260 Load Needed

Range Update:

I'm still on the hunt.
I dropped to 41.8gr of H4350 and chrono'd at the range.
Due to slightly higher ambient temps, I'm getting above the 2680fps I reported above, closer to 2700fps. But, still some pressure signs. So, next round I'm dropping to 41.5gr H4350 (still using BR2 primers for now).

Keep in mind, I'm shooting/chrono'ng at altitude (5600').
100 yd groups are good and decent accuracy out to 425 yds yesterday at a P_Dog match (with the 42.0gr loads).
Still, I'm hoping to settle at 2650fps and have brass I can shoot a few times.

 

[bohem]

Re: AR10 Specific .260 Load Needed

Below is my data for the LR-260 that I have. Loads are warm, and the brass cycles out in about 5-7 loading cycles.

123 Amax
Win 243 Brass, necked up and prepped
45.0gr H4350
CCI #200 primer
COAL 2.800"
2925 fps from 24" 1:8.5tw tube

140 Amax
Win 243 Brass, necked up and prepped
42.0gr H4350
CCI #200 primer
COAL 2.800"
2700 fps from 24" 1:8.5tw tube

 

[BCP]

Re: AR10 Specific .260 Load Needed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 19Scout77</div><div class="ubbcode-body">BCP- While I appreciate your admonition and sorry if I some how inconvenienced you</div></div>

I'm sitting on my ass drinking coffee, there's no inconvenience here.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">but nothing in the load you cited in any way references its use in an AR.
</div></div>

Other than COAL to make it fit in the mag there's nothing to worry about. I load my bolt loads the exact same way I load AR loads. So go take a look at that thread I referenced, get an idea of the types of brass, primers, powders and bullets people are using, and make some ammo. And enjoy your rifle!

 

[k2peaker]

Re: AR10 Specific .260 Load Needed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BCP</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 19Scout77</div><div class="ubbcode-body">BCP- While I appreciate your admonition and sorry if I some how inconvenienced you</div></div>

Other than COAL to make it fit in the mag there's nothing to worry about. I load my bolt loads the exact same way I load AR loads. So go take a look at that thread I referenced, get an idea of the types of brass, primers, powders and bullets people are using, and make some ammo. And enjoy your rifle! </div></div>

I'm a full 2 grains under my bolt gun load (43.6gr H4350, AIAW, Krieger 26" barrel, TBAC can) than in my AR10 .260 (JP LRP, 22" barrel, 1in8"tw, Cooley Lg comp). And, the COAL differences of course.
Bohem's post is similar to my experience.

 

[bignada]

Re: AR10 Specific .260 Load Needed

DO NOT load IMR or Hogdgon's 4350 except in bolt rifle. Burn curve is too slow and will beat up your gun.

Look to Varget, RL 15, IMR4064, IMR4895. Might get away with using XMR4350 as it is the fastest burning of the three 4350 mixes, but why risk damaging your expensive rifle?

 

[19Scout77]

Re: AR10 Specific .260 Load Needed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bignada</div><div class="ubbcode-body">DO NOT load IMR or Hogdgon's 4350 except in bolt rifle. Burn curve is too slow and will beat up your gun.

Look to Varget, RL 15, IMR4064, IMR4895. Might get away with using XMR4350 as it is the fastest burning of the three 4350 mixes, but why risk damaging your expensive rifle? </div></div>

Intersesting. I have a boatload of Varget, so no problem there. Any recipes?

 

[Jerkface11]

Re: AR10 Specific .260 Load Needed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bignada</div><div class="ubbcode-body">DO NOT load IMR or Hogdgon's 4350 except in bolt rifle. Burn curve is too slow and will beat up your gun.

Look to Varget, RL 15, IMR4064, IMR4895. Might get away with using XMR4350 as it is the fastest burning of the three 4350 mixes, but why risk damaging your expensive rifle? </div></div>

Use the powder you want if the gun is cycling too violently go to a heavier buffer. Or an adjustable gas block.

 

[19Scout77]

Re: AR10 Specific .260 Load Needed

I'd rather make up a load around a rifle than rifle around a load. Either way, in no way addresses the original post.

Anybody have a 123 load using Varget? Preferably shot out of a 20" AR.

 

[bohem]

Re: AR10 Specific .260 Load Needed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bignada</div><div class="ubbcode-body">DO NOT load IMR or Hogdgon's 4350 except in bolt rifle. Burn curve is too slow and will beat up your gun.

Look to Varget, RL 15, IMR4064, IMR4895. Might get away with using XMR4350 as it is the fastest burning of the three 4350 mixes, but why risk damaging your expensive rifle? </div></div>

This pontification is highly dependent upon port size, gas block, and port location along the barrel, as well as the bullet design and weight, and the powder charge used.

Just because 1 combination is bad for 1 gun doesn't mean a different bullet, buffer spring, gas block, barrel length, or bullet choice won't work with the x4350 series powders.

 

[Pat M]

Re: AR10 Specific .260 Load Needed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bignada</div><div class="ubbcode-body">DO NOT load IMR or Hogdgon's 4350 except in bolt rifle. Burn curve is too slow and will beat up your gun.

Look to Varget, RL 15, IMR4064, IMR4895. Might get away with using XMR4350 as it is the fastest burning of the three 4350 mixes, but why risk damaging your expensive rifle? </div></div>


?? I use H4350 in my DPMS .260 gas gun (1000+ rounds) no problems

 

[bowslngr]

Re: AR10 Specific .260 Load Needed

H4350 works great in my LR260 WITH 140 grain bullets. With lighter bullets, I get port pressure problems well before I reach the velocities I am looking for.

 

[1Sg (ret)]

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