260 Loads Only

[hueys66]

How about just a 260 thread? Be thorough on data.

 

[our gang]

Re: 260 Loads Only

May I suggest that if you have 140gr bullets and 4350, the rest is interesting but will do no better ?

 

[Short Round]

Re: 260 Loads Only

OK, here goes seeing as I was one wanting to break out .260 from the 6mm and 6.5 pack of mess thread.

Rifle; FN SPR with 25.5" Rock Creek barrel 1:8 twist.

Brass RP
Bullet 142 SMK seated to 2.830 (0.020 jump)ETA- was a bigger jump I found out when my stoney point mod casing came in! I was 0.037 deeper than I thought. Still 2.830 is mag length for me.

Primer GM210M (only a couple boxes left :-( )

powder H4350

*I started with IMR 4350 data so I'm low to start. I didn't realize how low until I got back on line and looked up Hodgdon's data site. Oh well, they're a start and I'm still breaking things in. Current round count after this is 101 so I'm still getting settled.

Average velocity for 5 shot groups

39.6 --- 2541 fps (groups; 0.99 std group, 0.67 rd. robin )
40.0 --- 2590 fps (0.9, 0.9)
40.4 --- 2618 fps (0.47, 1.28) best group and worst group
40.8 --- 2652 fps (0.95, 0.57)

control round; Black Hills Gold 139 Scenar Av 2689 fps. Heck I haven't even got to the Hodgdon starting load of 41.5 yet! Hodgdon always runs a bit to the warm side anyhow in my opinion.

I did a second set of groups going round robin this time and paced myself pretty slow and saw velocity climbing 10-25 fps over the first groups. Either she was getting faster with break in/ fouling or the late day sun was spoofing the electronic eyes. The data set was incomplete due to low sun though. Only 2 out of 5 shots were chronographed before the sun shut me down.

I'm not stopping here! Only just getting started.

ETA- more data as the work progresses.

41.6 --- 2653 fps groups 1.0 78 deg F and climbing, 8-10mph swirling winds
41.9 --- 2702 fps 1.0
42.2 --- 2721 fps 1.76 for 5 (1.15 for best 4) 81 def F, 10 mph gusting
42.2 --- 2713 fps 10 shots 1.2 inch, 76 deg calm/no wind (same day 2 hours later)
42.5 --- 2735 fps 1.2 at 81 deg F with 8-10 mph winds
42.5 --- 2733 fps 1.6 for 9 shots at 76 deg calm/no wind

I'm not finding any great consitent loads yet, still hunting. After 42.0 grains of H4350 I started to get some flattening but nothing harsh yet. I was hoping to get some good tight groups before going into the hot zone as I'm using RP brass that's not noted for long life.

Next steps are varied seating depths then powder type swap, then come another bullet. I'll have to go read that 6.5 Berger bullet thread again.

 

[DBL LUNG]

Re: 260 Loads Only

What kind of seating depth are you guys running the 139 Scenars at?
Do they like to jump, or should they be closer the the lands?
How far off the lands you running them?

Thanks, Josh

 

[Triggerhappy]

Re: 260 Loads Only

I jump mine .015" and get .25 - .35moa out to 500yds.

 

[DBL LUNG]

Re: 260 Loads Only

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Triggerhappy</div><div class="ubbcode-body">I jump mine .015" and get .25 - .35moa out to 500yds.</div></div>

Thanks for the info.
I'm gonna try a couple different seating depths.
I have settled on 42.3g of H4350.
Consistency has been good with only a couple feet per second difference between shots with this load, while still grouping good.
But I would still like to tighten up the groups.
Right now its around .85 to .50 @ 100, but I think it can do better.
The 139g Scenars are seated about .055 off the lands right now, but I have room to seat them further out in the magazine.

 

[BOLTRIPPER]

Re: 260 Loads Only

i still do 144's w/43grn/4350 loaded out to mag length

 

[DBL LUNG]

Re: 260 Loads Only

Just finished loading up 32 rounds of .260.

139g Scenar, Rem Brass, CCI BR2, 42.3g H4350

4 @ 2.252 - .030 to lands
4 @ 2.257 - .025 to lands
4 @ 2.262 - .020 to lands
4 @ 2.267 - .015 to lands
4 @ 2.272 - .010 to lands
4 @ 2.277 - .005 to lands
4 @ 2.280 - .002 to lands
4 @ 2.285 - .003 jammed
(lengths are measured with Stoney Point .264 Comparator to o-give)

My current load is 2.227 - .055 off the lands.
Tomorrow's forecast is supposed to rain, but Sunday I will hopefully get out and try these loads.

What distance do you guys normally shoot for load development?

 

[Triggerhappy]

Re: 260 Loads Only

I normally shoot 300-400yds for load development. Sometimes you notice things at these distances that are not apparent at closer distances.

 

[michael_aos]

Re: 260 Loads Only

43.5gr H4350
139gr Scenar
Winchester 7mm08 brass, CCI BR2 primer
Flash-holes deburred, COAL ~2.82"

Right at 2800fps from my 22" 1:8" twist Lilja.

I'm running low on H4350 though. Was thinking I might try H4831sc, but can't find it anywhere either.

Anyone tried RL17 yet? Powder Valley has it in-stock.

 

[DBL LUNG]

Re: 260 Loads Only

I was able to get out and shoot on Sunday with the different bullet seating depths.
The best groups came at .020 off the lands @ 2824 fps.

139g Scenar, Remington Brass, CCI BR2, 42.3g H4350.
For some reason on Sunday I was seeing larger spreads in the fps than normal. It was actually cool outside, only about 70 degrees.

One strange issue was the bolt sticking pretty good after a couple of the shots.
I fired 32 rounds total and 14 of these shots had extractor marks on them. I can't figure out why. The funny thing was that it happened at all different bullet seating depths, so I don't think it was because of where the bullets was seated (building pressure). I have had maybe one or two rounds do the same thing at the normal seating depth (.055 off the lands), but not like this before.

Any idea on what would be causing the extractor marks?

 

[NRAShooter]

Re: 260 Loads Only

The extractor marks are most likely caused by pressure. Your primers appear to also be slightly cratered too.

Happens to me too sometimes. I use 44.0 gr H4350 with a 142 gr SMK CCI BR2. I find after 3 to 4 reloads the brass gets soft and I start to see high pressure signs. No big deal, I toss the cases with loose primer pockets or extractor marks and keep going.

 

[DBL LUNG]

Re: 260 Loads Only

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NRAShooter</div><div class="ubbcode-body">The extractor marks are most likely caused by pressure. Your primers appear to also be slightly cratered too.

Happens to me too sometimes. I use 44.0 gr H4350 with a 142 gr SMK CCI BR2. I find after 3 to 4 reloads the brass gets soft and I start to see high pressure signs. No big deal, I toss the cases with loose primer pockets or extractor marks and keep going. </div></div>


Do you think I should try some new brass?
The Remington brass that I am using now was purchased along with the rifle and maybe has 4-6 reloads.
I have personally only reloaded them twice.

What kind of speeds are you seeing with your setup?
Thanks for the info, Josh

 

[ChadTRG42]

Re: 260 Loads Only

Josh,

You have high pressure on those loads. I would back it down on the charge weight. If the brass still has firm primer pockets, then the brass is still good. But on the one's with the extractor marks, you may have stretched the pockets with the high pressure. You are right at max already, and are over max in your gun. So, I'd reduce you charge weight and see what shoot s well.

Chad

 

[NRAShooter]

Re: 260 Loads Only

I agree with ChadTRG42. You probably should toss the cases with the extractor marks as there's a good chance your brass is starting to flow due to the higher pressure. You might want to experiment with other primers after reducing the powder charge. Shoot over a rest with a chrono and record your results. Try not to add too many variables or you'll go crazy trying to figure out what is causing what.

In my set up I am getting 2880 fps with a 139 gr. Scenar and the load I previously listed. Haven't chronographed the 142 gr SMK yet, but they are equally accurate.

I start with new brass and am starting to find that by the third reload the brass is starting to get soft. I say this as the brass sizes real easy, trims like butter and the primers pop out easily when I resize the cases. On the fouth load I am starting to experience high pressure signs similar to yours. Sticky bolt, extractor marks, and what appears to be leaky primers in the form of an incomplete black ring between the primer and primer pocket.

So what does this all mean to me? In my un scientific way, I will load my rounds three times and toss them afterwards. I like the loads I've developed as they shoot great and have a low SD. I've experimented with lighter charges and don't get the level of accuracy or consistency I am experiencing with my current load.

My set up is:

GAP Surgeon SA, 28" fluted Broughton Barrel no. 7 contour, Badger FTE brake, AICS 2.0 w/adjustable buttplate and cheekpiece screws, Jewell HVR trigger set at 12 oz, Badger Rings, NF NXS 8x32x56 MLR, Harris Bipod with pod loc.

Once I dial in my load recipe, I load all my ammo on a Dillon 650.

Your results may vary. Good luck.

 

[Greg Langelius *]

Re: 260 Loads Only

My guess is that after 4-6 reloads the case length may be starting to exceed 2.035". That's max length (trim to 2.025"), and they don't all arrive there in the same reloading, which might explain why some show pressure and some don't.

Odds are good that if this is the culprit, the excess length-related pressure spike may be a contributing factor in the loosening of the primer pockets. That chicken does precede that egg.

Brass isn't the only commodity at risk here, I've seen an excess length case blow up a gun. The owner was stumped about why, until he disassembled his rounds and checked case length. Sure enough, a percentage of them were overlength, and a small few were doozies. Not definitive, but very suspicious.

Greg

 

[Supersubes]

Re: 260 Loads Only

In my GAP .260 i was never able to run 42 grains of H4350, it would just trash the very soft Remington brass.

Lapua 139
Remington case
CCI BR2
40.7 gr H4350
seated to mag length
2800 fps.24" rock barrel.

I just switched to 6.5X47. For mag length seating, it is everything the .260 is without the sketchy brass.

 

[BOLTRIPPER]

Re: 260 Loads Only

damn.....

just dayem....


Boltripper must be leading a clean life 'cause before i see ANY FUCKING signs of pressure on the ass end of the case....i will have already seen daylight through the necks.....in which case i toss'em.....and this is after...way south of 6 or 7 loadings.....

 

[Greg Langelius *]

Re: 260 Loads Only

I wonder how the GAP would perform with 34-36gr of Varget, which should be significantly faster than H4350. Without knowing specifics about how the cases were getting trashed, I am curious whether the wreckage might be a product of excessive port pressures. While I have a comfortable level of experience with .260 loads for the bolt guns, the same is not true of AR-type rifles and the .260 loading. I'd be grateful for any handloading lore such owners could share.

My experience with semi's is mainly developed from feeding Garand, M1A, and AR15/223 rifles. My mentors all advised against heavy bullets and slower powders, with the greatest emphasis with the Garand, and descending emphasis with the M1A, and finally the AR. The thinking expressed was all centered on port pressures, and the relationship between them and propellant burn rates. Consequently, I have always been a tad nervous when folks talk in combinations of semi's, heavier bullets, and slower powders.

If I had an AR10-ish implement running a .260 chambering, I'd be choosing a longer barrel, 1:8.5-1:9" rifling, a longer distance between chamber and gas port, and be limiting my loads to 120gr bullets and lighter and charges similar to the 34-36gr Varget loads that were recommended to us by the truly serious bolt gun shooters back at the SOA Match in 2002. I would consider such loads to be truly compatible between bolt guns and gas guns, and be relatively effective and efficient in both.

As has been recently pointed out to me, my knowledge in this area is lacking, so any help folks could provide me would go some distance toward remedying this, and I would be suitably grateful.

TIA.

Greg

 

[Supersubes]

Re: 260 Loads Only

The problems I had with the brass was enlarged primer pockets. Never experienced anything like it in any other chambering. Durinng load developement I think I went to 43 grains. On the outside all looked fine, accuracy was great everywhere. Upon reloading them, most of everything around 42 gr wouldn't hold a primer. As I backed charges down to the 40gr range, the problems stopped. I experienced this through two lots of brass, including the GA/black hills .260 loaded ammo.

Greg, you and I exchanged a few PM's on this issue. I had contacted you because you had posted about oversize pockets in a batch of .260 brass you came across.

 

[DBL LUNG]

Re: 260 Loads Only

I picked up 100 new Remington brass today.
I am going to run another ladder test with lower charge weights.
I didn't think 42.3 grains was near the high end of H4350.
I have seen several people running up to 44 grains, so I thought 42.3 would be ok.
On my last ladder test, I went up to 44 grains and didn't have any negative signs.

Maybe its just old brass.
I will try the ladder test this weekend and see how things go.

Thanks a lot for the help guys.
I'll post back with my results.

 

[Triggerhappy]

Re: 260 Loads Only

I did not notice anyone else saying anything about seating depth effecting pressure, but it can dramatically effect the chamber pressure of a load. I have a 308 Varget load that is close to 2 grains over Hodgdon's max load with no pressure signs. This load is also about .25" over magazine length but it shoots great.

 

[DBL LUNG]

Re: 260 Loads Only

Went out and tried some more ladder testing with lower charge weights.

Started at 39.5, 39.8, 40.1, 40.4, 40.7 & 41.0 grains of H4350.
I am actually still seeing some ejector marks on the brass even at 39.8 grains which is only 2706 fps. Primers are slightly cratering even at the lower charge weights. The 41.0 load averaged 2796.

Could it be the BR2 primers?
Would standard CCI 200's help any?
I am completely baffled.

What do you guys think I should try, or what could be the culprit?


Thanks, Josh

I should note that this is new RP Brass.
Trimmed to 2.025.

 

[DBL LUNG]

Re: 260 Loads Only

Here's some pics of 39.5, 39.8, & 40.1.
Are these primers considered "cratered".
Ejector marks are shown on some, but not all.

 

[DBL LUNG]

Re: 260 Loads Only

Update

Shot the same ladder test today with BR2's and CCI 200's.
H4350, same loads as before (39.5, 39.8, 40.1, 40.4, 40.7, 41.0).
This time I seated the bullets a little further back in the case, thinking that the pressure may have been because the bullet was possibly jammed into the lands.

I didn't have a single ejector mark today, but my speeds dropped off about 20-30 fps.
The CCI 200 primers were about 30 fps slower in the same charge as a BR2.

Trying another ladder test tomorrow with 40.1, 40.4, 40.7, 41.0, 41.3, 41.6, & 41.9 to see what the speeds and groups do while I watch for pressure signs.

 

[pinzmann]

Re: 260 Loads Only

I'm running 45.4gr of 4831sc behind 139gr Lapuas with Rem brass. This is in a Shilen barreled Rem700 action. Getting 1/2 MOA groups out to 500 yds. Also have a Savage target action which likes 46gr of R22 with the same bullet. The Savage has pre chambered Shilen barrel. Got some pressure signs this summer{100deg plus} with the savage so I dropped it down to 45.5gr. I think I was getting 2875fps with the 700 and a little over 2900 with the Savage.

 

[4Rail_Gunner]

Re: 260 Loads Only

Finally Settled on a Load.
Rem 260, Rem 700 action trued.
Kreiger 1 in 8.5 twist.
26" Long
Rem 260 Brass
GM210M Primer
43.0gr H4350
142 SMK
Loaded to .025 off Lands
Sub MOA Across the Board.
2870 FPS

 

[michael_aos]

Re: 260 Loads Only

These velocities seem especially high.

Can you guys include barrel-length as well?

 

[Red Ryder]

Re: 260 Loads Only

pinzmann what barrel length and twist? thanks.

 

[DBL LUNG]

Re: 260 Loads Only

26" Shilen
For some reason I can not load as hot as other .260 owners.
I start seeing pressure signs (ejector marks) at about 41.0 grains of H4350 with BR2 primers.
But, its not every round. I only see ejector marks on every couple of rounds.
It seemed like this weekend that the pressure signs started to show when the barrel got warmed up.

 

[Red Ryder]

Re: 260 Loads Only

DBL Lung how many rounds have been down that barrel?

 

[DBL LUNG]

Re: 260 Loads Only

Around 850-900

 

[Short Round]

Re: 260 Loads Only

If I was you (which I'm not ;-)) I'd take the brass from the last batch of firing with the ejector swipes and measure the neck thickness just to see if there is any serious variation. Secondly I'd weigh them with water in them and see if I could detect a volume difference between those with and those without the ejector swipes.

Tonight I'm playing with a new Sinclair premium neck turner and I'm playing with some remington .243 brass. I am getting some wide swings on neck thickness 0.0152" on one side and 0.0132 on the other is just one I noticed. Sounds like shitty brass and I suspect I'll find the same with my RP .260 brass.

 

[DBL LUNG]

Re: 260 Loads Only

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Short Round</div><div class="ubbcode-body"> If I was you (which I'm not ;-)) I'd take the brass from the last batch of firing with the ejector swipes and measure the neck thickness just to see if there is any serious variation. Secondly I'd weigh them with water in them and see if I could detect a volume difference between those with and those without the ejector swipes.

Tonight I'm playing with a new Sinclair premium neck turner and I'm playing with some remington .243 brass. I am getting some wide swings on neck thickness 0.0152" on one side and 0.0132 on the other is just one I noticed. Sounds like shitty brass and I suspect I'll find the same with my RP .260 brass. </div></div>


I just got done doing some measurements on two different charge weights.

First Charge 40.1 grains H4350
40.1 grains had no pressure signs and grouped well, but was only between 2672 - 2689 in 4 shots with a dirty barrel.
This load is normally around 2700 - 2710 with a clean barrel.

------ Grains -------- Neck
Case - Empty - Water - OD - ID
-- 1 - 167.0 - 222.3 - .298 - .266
-- 2 - 167.6 - 223.0 - .297 - .266
-- 3 - 167.4 - 222.7 - .298 - .266
-- 4 - 167.0 - 222.4 - .297 - .266

41.0 grains showed a little primer flattening and cases 2 & 3 showed ejector marks. Speeds were between 2726 - 2741 on four shots with a dirty barrel. This load is normally around 2740 - 2760 with a clean barrel.

------ Grains -------- Neck
Case - Empty - Water - OD - ID
-- 1 - 167.8 - 223.0 - .298 - .267
-- 2 - 168.0 - 223.2 - .298 - .266
-- 3 - 167.6 - 222.5 - .298 - .266
-- 4 - 167.8 - 222.6 - .298 - .267

I don't have a neck wall thickness gauge, so the outside diameter and inside diameter of the necks were taken with my digital calipers.

Nothing really sticks out to why I am seeing pressure signs with such a low charge and low chrono speeds.

I have my bullet jumping to the rifling (about .055 off the lands), so a jammed bullet shouldn't be causing the pressure signs.

I'm lost. I may just stay with 40.1 grains at around 2700 fps and call it good. I'd like to get around 2800 which would be about 2.5 less MOA at 1000 yards compared to 2700 fps.

As always, any help or direction is greatly appreciated.
Josh

 

[Short Round]

Re: 260 Loads Only

Well I don't see anything from your data that jumps right out and smacks me. I definitely see the ejector swipes though. Perhaps one of the more experience guys will see something there. I wouldn't really trust numbers on the neck like you've taken with a blade mic with a 0.001" resolution. Mitotoyo ball mic would serve the purpose better.

Today's my day off and I'm on to playing with my RP .260 brass that has four firings on it. I got 2 loose pockets out of 60 casings so I'm starting to play with it setting up the neck turner. I realize you true brass when new but what the heck.

-I'm seeing a lot of donuts. I figured I'd find them as I was having a big difference in feel when seating bullets. I'm assuming my method for donut removal is ok. Instead of reaming from the inside, I've expanded the necks with a sinclair expanding die and subsequently turned them on the outside of the neck. I never got the donut feel in an empty unresized case (slip fitting a bullet for resistance). I do see them for a millimeter or two forward of the shoulder junction.

I wonder if you're getting bit by donuts?

I was getting groups that would touch 3 in one place and toss two an inch away together. I was frustrated to say the least, so now I'm uniforming necks.

I'll play with this worn RP brass in my hunting rifle but I'm not tossing a 142 SMK downrange w/o some lapua brass.

 

[ChadTRG42]

Re: 260 Loads Only

You're definitly getting pressure on the 41.0 load. I would switch powders, and see what happens. Try H4831 or R17 or R19.

 

[DBL LUNG]

Re: 260 Loads Only

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">You're definitly getting pressure on the 41.0 load. I would switch powders, and see what happens. Try H4831 or R17 or R19. </div></div>

What's a good starting point for H4831?
How about H4831sc?

How about Varget?
I run Varget in my DPMS .308 and my .22-250 and I have plenty on hand?

 

[Red Ryder]

Re: 260 Loads Only

i told him in a pm that i had the exact same things happening to a 308 that had developed headspace problems after less than 1000 rounds.

any of you guys think it could be headspace problems?

 

[DBL LUNG]

Re: 260 Loads Only

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Short Round</div><div class="ubbcode-body">

I wonder if you're getting bit by donuts?

I was getting groups that would touch 3 in one place and toss two an inch away together. I was frustrated to say the least, so now I'm uniforming necks.

I'll play with this worn RP brass in my hunting rifle but I'm not tossing a 142 SMK downrange w/o some lapua brass. </div></div>


I checked all of the non-pressure cases and the pressure sign cases for any type of donuts. Not a single one on any of them.
I used a bent paperclip to check the insides of each case and they all feel fine. There are no visible interior or exterior donuts on any of the fired cases.

 

[Short Round]

Re: 260 Loads Only

I think a donut would be a little too subtle to check with a paper clip.

Are you looking inside down by the case web? that's not donuts, that is for case seperation. That's where I use a sharpened bent paperclip.

For donuts, try taking an unresized piece of brass and slip a bullet in the neck. It should drop right through, if it hesitates or stops in the shoulder junction you found a donut.

Pardon if you already knew that, it's just that I never heard of checking for donuts with a paper clip.

SR

 

[rksimple]

Re: 260 Loads Only

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DBL LUNG</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">You're definitly getting pressure on the 41.0 load. I would switch powders, and see what happens. Try H4831 or R17 or R19. </div></div>

What's a good starting point for H4831?

</div></div>

I run 46.5gr in necked winchester 7mm-08 cases with the 142 SMK. Start around 44-45 and work up.

 

[CowboyBart]

Re: 260 Loads Only

My hunting load is:
139gr PMC bullet (Pointed Soft Point- flat base)
36gr IMR 7383 (mil-surp 50 BMG spotter powder)
CCI #34 primer
R-P 243 brass
OAL: 2.855" (this is into the lands of my Encore - but that is the way it likes it)
.47" @ 100 yds
No chrono info yet.

T/C Encore 24" w/ 8" twist

 

[Short Round]

Re: 260 Loads Only

Finally got a hunting load that was acceptable in my FN build with #5 contour 1:8" 24" Rock Creek Barrel with standard SAAMI chamber.

130 Accubond seated to jump 0.010" OAl 2.815 (Fortunately fits well in SPR detachable magazine at land contact)
RP brass
Wolf Primer
Nosler's max; 47.5 H4831SC. She wouldn't tighten up before that and I was getting irked blasting expensive bullets!

I'm getting 1.25" at 100. Nothing to write home about but she was a lot worse before reaching max.

I might sub the WLR for the Wolf, try seating some deeper and reworking it a tad.

FYI chrono info at 65 deg F.

47 H4831SC yeilded 2701 fps, ES 17, SD 5, 2 1/4" group
47.2 H4831SC yeilded 2711 fps, ES 46, SD 14.9, 2 1/8" group
47.5 H4831SC yeilded 2721 fps, ES 31, SD 10.6, 1 1/4" group

Nosler's manual had a expectant velocity of 2818 fps with RP brass and Rem 9 1/2 primers with 47.5 H4831SC.

Running Black Hills factory 139's through her I get 1.1 inches at 2640 fps at 65 deg F.

 

[michael_aos]

Re: 260 Loads Only

I tried working up a 260 Remington hunting load a couple years ago.

RP 260 brass, Federal 210M primer, VV N550, and the 130gr Swift Scirocco II bullet.

I just never could it it to group worth a darn in my Remington 700 Titanium. Something like 8" groups at 100yds.

Finally just gave up and bought a Remington 700 SPS Stainless in 270 WSM.

 

[Short Round]

Re: 260 Loads Only

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Michael Aos</div><div class="ubbcode-body">I tried working up a 260 Remington hunting load a couple years ago.

RP 260 brass, Federal 210M primer, VV N550, and the 130gr Swift Scirocco II bullet.

I just never could it it to group worth a darn in my Remington 700 Titanium. Something like 8" groups at 100yds.

Finally just gave up and bought a Remington 700 SPS Stainless in 270 WSM. </div></div>

Ha! I can relate, the whole reason for the .260 build was the totally erratic performance of a .308 700 Ti mountain. The .260 has not been an easy performer either though. In contrast my Obermeyer barreled .308 would shoot submoa if I loaded broken glass and charcoal for a load, she's just a pleasant lady and these other rifles are contrarians.

 

[Rich Emmons]

Re: 260 Loads Only

140 AMAX (42-43g) H4350 will produce sub MOA groups and is great for deer.

 

[Short Round]

Re: 260 Loads Only

Well seeing as deer season wasn't quite on me yet I continued to play with the .260 hunting loads.

I played with the 140 Sierra Game King seated 0.010" off the lands.

43.3 H4350
RP brass,fully prepped including cleaning up the necks.
WLR primer

V 2724fps
ES 28
SD 9

I haven't shot it at 100 yards, just 200 and 300. (it's my new thing to get the heck away from the 100 yard line)

200 yards, 5 shots neatly arrayed in an 1.2"
300 yards 2.8" from a just cleaned bore, first 2 shots were about 60 fps low. I had to clear out due to range time limits on sunday before firing another group.


For my other .260 rifle, the heavy barrle one I played some more with the 140 SMK. Conditions; 8-15mph winds, shifting from a tailwind to 90 deg L to R crosswind.

140 SMK with a 0.010 jump
43.1 H4350
WLR
RP brass fully prepped and necks cleaned up
My neck tension is at 0.004" until I get another bushing. Too much!

1st 300 yard group; 2", 2784fps, 12 ES, 3 SD
2nd 300 yard group; 1.85", 2785fps, 21 ES, 8 SD

140 SMK with a 0.010 jump
43.3 H4350
WLR
RP brass fully prepped and necks cleaned up

1st 300 yard group; 2.75", 2780fps, 20 ES, 6 SD
2nd 300 yard group; 2.65", 2801fps, 21 ES, 9 SD

140 SMK with a 0.005 jump
43.3 H4350
WLR
RP brass fully prepped and necks cleaned up

1st 300 yard group; 2.3", 2793fps, 54 ES, 19.9 SD

I was getting slightly sticky bolt lift at 43.3 H4350 for approx 50% of rounds. None with 43.1 H4350. Methinks the ticket is 43.1 H4350.

Still in search for the one hole group an a million yards.

 

[yavapai kid]

Re: 260 Loads Only

Rem 700 22" barrrel
Lapua 243 brass necked up
Win primer
130 Accubond
Ramshot Hunter 47.0 grains.

2,900 mv .6-.7 groups

 

[dar1246]

Re: 260 Loads Only

Tried something new today. Built a 260 with a 30" barrel.

43.5grs H4350
139 lapuas SC
Rem brass
CCI BR2 primers
COAL 2.835
fps 2960

No pressure signs.

 

[michael_aos]

Re: 260 Loads Only

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dar</div><div class="ubbcode-body">Tried something new today. Built a 260 with a 30" barrel.

43.5grs H4350
139 lapuas SC
Rem brass
CCI BR2 primers
COAL 2.835
fps 2960

No pressure signs. </div></div>

Just as a data-point, I'm running an extremely similar load with a 22" barrel. Averaging ~2800fps with some shiny spots on the brass.