260 Loads Only

[AC Power]

Anybody seen a 2000MR load pushing berger 130VLDs for 260? Got a bunch of that I'd like to use if I could but can't find jack for a starting point.

 

[Nautijohnson]

Anybody seen a 2000MR load pushing berger 130VLDs for 260? Got a bunch of that I'd like to use if I could but can't find jack for a starting point.

Alliant Powder - Reloader's Guide
this is all I could find, 120gn bullet with 40gn of 2000mr. So maybe start your load work up at 38.5gn. click link above. -Ashton

 

[timjoebobbradley]

I have an oddball question- I have some .243 brass I want to make into .260. I can do the neck expansion just fine, but when I do this with winchester brass the primer will get a light strike and not fire, but with Lapua brass it fires every time. The shoulder starts at the same point on each round, but the shoulder angle is steeper for the 260. Is the lapua brass just a little thicker and resists being pushed forward enough for reliable primer strikes but the winchester doesn't? I haven't looked at this loaded ammo for a while, but thought I should fix this problem or pull the bullets and see if I can make it work.

 

[Hondo64d]

I've got 5# of Hunter coming. It was the only powder I could find. It SHOULD work great with everything from 120s to 140s since it's burn rate is about that of R19, but like you, I'm not finding much data for it. I'll be sure and post my results...

John

Well, gave Hunter a good try and just couldn't find any accuracy with it. Velocities were very good, but no accuracy at any charge weight with bullets that have always shot very well for me. Results were poor enough that I'm not going to even post them.

7828ssc was just as bad. R17 is showing promise.

John

 

[trailrider121]

Hondo,

No luck huh. I use Hunter in my 30-06, and found that Hunter produces best groups when pushed towards the max charge. Bummer I was hoping to hear good results from your testing. I was going to try Ramshot Hunter, probably not now. I'll stick with H4350 till I run out. Thanks for the update.

 

[AdamP]

has anyone messed with the 107gr SMK. I got a bunch in trade but cant find any data

 

[Sargesniper]

<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

Josh,have you tried any other brand of brass? If not, you may try win. .243 brass necked up to .260. Better brass, to me anyway. ..... SEMPER FI!

 

[Ring]

260
123 amax
col 2.870
44.3 H4350
2933FPS

 

[popeye089]

Lapua 260 Brass
Federal 210 primers
41.1gr N550
136 Scenar L
seated .020 off lands
average speed 2820
sd 8

Lapua 260 Brass
Federal 210 primers
40.8gr N550
139 Scenar
seated .020 off lands
average speed 2775
sd 10

 

[Unknown]

I just looked, and Powder Valley shows Nosler 140 grain 6.5mm custom competition bullets in stock, in both 100 and 250 count boxes. Nice price too.

 

[AMG04]

has anyone messed with the 107gr SMK. I got a bunch in trade but cant find any data

I tried an OCW test with 107gr SMKs over RE-17, but they did not shoot well in my 8-twist barrel. The test loads ranged from 46 grains up to 47.4 grains (don't have chrono numbers handy right now). I may not have done the bullet justice by only testing one powder and one COAL, but I didn't see the point to continue. The 140 class bullets shoot great for me.

I hope you are better served by the 107's than I was. Best of Luck.

 

[bogeybrown]

Tag for some great info once I FINALLY break down and buy my .260

 

[Bradu]

Remington .260 brass
CCI #200 Large rifle primers
42.1 grains H4350
142 smk loaded to coal 2.80

No clue on fps, still need to buy a chronograph. I know it's not very fast out of my rifle with a 22" barrel, the bullet drops more than a FGMM 168 out of my AI.

 

[wchartz]

If you want a load using Varget try this. 123 SMK, 41.3/Varget, Lapua brass, Fed 210M. The bullets are Boron Nitride coated so It takes about .5 gr. more powder to achieve the same velocity as with an uncoated bullet.
I get 3001 fps in a 25" barrel bolt gun. The brass is on the ninth loading and I foresee several more loadings. I get 5 shot groups in the .375 MOA range, some may go as high as .5 MOA. My last 600 yd. five shot group was 2.28" shooting off the ground using my Harris bipod and field bag. This load easily bangs 12" plates at 1000 yds. The gun is a Beanland build using a Kreiger standard Palma in 8.5 twist. I'm happy with it.

 

[thespecialist]

RP 260 brass
CCI 200's
43.9gr H4350
140 Nosler Custom Competition loaded to 2.760" (.005" off the lands in my AAC barrel)

Runs 2745fps from a 20" AAC barrel with zero pressure signs. Definitely not as fast as 24+" of barrel, but it's no slouch.

RP 7-08 brass
123gr Amax
Wolf LR primers
44.6gr H4350

Runs 2875fps from my 20" barrel.

 

[Southpaw]

I’ve been experimenting with Hodgden Superferformance powder and thought my results were worth sharing.

These loads don’t show over pressure signs in my rifle, however, there is no published data for Hodgden Superferformance powder with the 260 Rem, so workup.

26” Bartlein 5R 8.5 barrel
R-P 243 brass
FC 210 primers

123 Sierra MK COAL 2.830

47.9 Hodgdon Superformance
5 shot group 0.398
3096 fps average
SD 19

48.3 Superformance
5 shot group 0.485
3121 fps average
SD 12

48.7 Superformance
5 shot group 0.596
3147 fps average
SD 18

49.0 Superformance
5 shot group 0.650
3144 fps average
SD 49

136 Lapua Scenar L COAL 2.820

46.7 Superformance
5 shot group 0.330
2995 fps average
SD 14

47.0 Superformance
5 shot group 0.708
3006 fps average
SD 10

47.3 Superformance
5 shot group 0.437
3037 fps average
SD 3

47.6 Superformance
5 shot group 0.470
3065 fps average
SD 20

 

[Sargesniper]

I’ve been experimenting with Hodgden Superferformance powder and thought my results were worth sharing.

These loads don’t show over pressure signs in my rifle, however, there is no published data for Hodgden Superferformance powder with the 260 Rem, so workup.

26” Bartlein 5R 8.5 barrel
R-P 243 brass
FC 210 primers

123 Sierra MK COAL 2.830

47.9 Hodgdon Superformance
5 shot group 0.398
3096 fps average
SD 19

48.3 Superformance
5 shot group 0.485
3121 fps average
SD 12

48.7 Superformance
5 shot group 0.596
3147 fps average
SD 18

49.0 Superformance
5 shot group 0.650
3144 fps average
SD 49

136 Lapua Scenar L COAL 2.820

46.7 Superformance
5 shot group 0.330
2995 fps average
SD 14

47.0 Superformance
5 shot group 0.708
3006 fps average
SD 10

47.3 Superformance
5 shot group 0.437
3037 fps average
SD 3

47.6 Superformance
5 shot group 0.470
3065 fps average
SD 20

Hi Southpaw, i have also tried Superformance in my .260 an got great results with the 120 gr. A-MAX. Over 3100 fps and one hole group @ 100 yds. Looking at your results confirms my thoughts on this powder. I felt like it could be pushed harder because i saw no pressure signs at all. The group was so good that i stopped at 47.0 gr. With your post here i can now think about the heavy bullets. Are the new 136 L's any better than the 139's? Also where did you find them? Thanks, ........ SEMPER FI!

 

[Southpaw]

Sargesniper, Although I could go a grain or two more with both bullets, I’m thrilled with these velocities, so why push it?
I’m going to try hotter primers and play with the seating depth as these groups are not the best I’ve shot with this rifle.

I split a box of 1000 Lapua 136s from Midway with a couple of friends. Whether these are better then the 139s remains to be seen.

 

[Sargesniper]

Superformance and the .260

Sargesniper, Although I could go a grain or two more with both bullets, I’m thrilled with these velocities, so why push it?
I’m going to try hotter primers and play with the seating depth as these groups are not the best I’ve shot with this rifle.

I split a box of 1000 Lapua 136s from Midway with a couple of friends. Whether these are better then the 139s remains to be seen.

I would hope they are very much better at $10.00+ more per 100. Wonder when the madness will end?
Yes i too feel like i could go higher but i'm getting one hole and 3100+ with the 120 gr. A-MAX out of a 30" Bartlein 8.5 twist barrel. I only think velocity would increase,not smaller groups. If they got any smaller they would measure .264" outside to outside. I do not know how the temp. will affect this powder but i live in Louisiana abd i shot this in the summer.
I have not tried Mag. primers,only Match so i cannot reply to that subject. I really want to go with the heavy bullets now that i know what it does with the lighter ones.I can't tell you that this load will shoot distance as i do not have a longer range than 100 yds close to me. Good luck and keep me informed on your progress. ........ SEMPER FI!

 

[CLNDESL]

I just picked up 8lbs of superformance so hopefully I can get 140 gr amax's to shoot. I'll let you guys know.

 

[Southpaw]

I would hope they are very much better at $10.00+ more per 100. Wonder when the madness will end?

These days, we have to work with whatever components we can get. I hope these were worth the money
I'll post updates here as load development progresses.

 

[Sargesniper]

These days, we have to work with whatever components we can get. I hope these were worth the money
I'll post updates here as load development progresses.

Thanks Southpaw, I'm interested. Post as soon as you can. ....... SEMPER FI!

 

[capnswervon]

I just picked up my new 260 Rem about 2 weeks ago. I am just now starting to get onto a load that works pretty well in the gun. It has been a bit frustrating because I have been shooting a 308 for a while and never had this much trouble getting a load that shoots. I will go over the specs and the load development that I have completed and then I have a couple of questions for you fine people with a little more experience with the high BC 6.5 bullets.

The Rifle:
Surgeon 591R
26" Hart 1:8' barrel chambered with a PTG Match Reamer with .060 freebore
AICS 2.0 with Viper Skins
Jewell Trigger
LRA Bipod
Steiner 5x25 MSR in Badger Max50's

The Load:
142gr SMK
Lapua Rem 260 Brass
H4350
Fed 210M

I have completed a simple ladder test between 38gr-44gr of powder and found that anything past 41.5 gr gets into the realm of pressure and speeds of over 2800fps. Also, at the higher speeds 2720+ the bullets will just not stabilize for me. Most of the time that means that you need a little bit more ass behind them but seeing as I just threw out 45 pieces of Lapua brass because of loose primer pockets after 2-3 loads I know I was already hot. I am out of the lands so I can rule out that factor of building early pressure.

Therefore, I have conducted more testing at the lower node and I am getting some good results around 40gr of H4350 at around 2650fps with SD's of 4-6. I am playing with seating depth now and have shot some consistent groups in the .3-.5 moa realm but I was really hoping for a bit more velocity out of this rifle with a 26" tube.

So, with that being said, would a slower burning powder such as H4361sc allow me to get into the next accuracy node without producing pressure and pick up about another 100fps?

I was hoping to stick with the 142smk's as I have 1000 of them but I do know that they are sometimes the most tempermental bullets out there. If need be, I can try to find other projectiles but this barrel was really built for the heavier bullets.

Any input would be greatly appreciated.

The Capn'

 

[bodywerks]

What kind of pressure realms are you seeing? I'm launching 140 amax at 2890 with the same length barrel under 43.3 grains 4350. Only pressure sign is very slightly flattened primers. No crater, no extractor marks, nothing.

 

[capnswervon]

Flattened primers, big extractor marks and blown out primer pockets. I even had 2 cases split near the base complete with hard bolt lift and a chunk of brass jammed into the ejector. They were hot!!!

The Capn'

 

[8nbait]

I concur, something is wrong if 41.5 of H4350 showing any kind of pressure but especially excessive pressure.

 

[bodywerks]

Flattened primers, big extractor marks and blown out primer pockets. I even had 2 cases split near the base complete with hard bolt lift and a chunk of brass jammed into the ejector. They were hot!!!

The Capn'

What is your oal? How much jump? And most importantly what brass? If its not lapua I'd seriously consider switching.
You have bad brass, are jamming into the lands, or both. You should be able to get 2800 minimum on a 26" barrel, no problem whatsoever, and not experience pressure.

 

[capnswervon]

Per my original post, I am using Lapua Brass and I am not jammed. I was right off of marriage for the initial tests but now I am .010 out and seeing better results in the lower node.

Admittedly, the brass was probably weakened by the first ladder test that I took to 44gr and over 2900 fps. On the first firing of the Lapua brass they were not showing pressure signs including the primers so I did not think too much about it. However on subsequent reloads I started to see pressure signs and the insipid case separation occurred at 42.5gr. At that point I stopped and chucked the brass starting over.

I can get the velocity but no accuracy along with it. They were flying at 2800 fps at 41.5gr of powder but scattering like a shotgun. Most of the time, that means that it needs more powder to stabilize but then I get the pressure signs.

One other change to point out. I initially was resizing with a Hornady FL resizer with an expander ball. It seemed like I really needed to crank the die down to get any type of shoulder bump back when measured with my chamber gauge that is made from my barrel stub and reamer. My theory is that I was also over sizing the brass which let to additional stress and too much headspace coupled with hotter loads.

I just received my Whidden FL resizer and it is about as close the the custom dies I had made for my 308 chamber as you can get. It does not use an expander ball and resizes just enough to get it done.

I am most likely going to go back to the 41-41.5 range again with brass that has not been stressed and work out of the lands .010 and see what happens.



The Capn'

 

[8nbait]

That sounds like a good plan. I was up to 45.7 gr of H4350 with the 130's and never did see any pressure signs. Perhaps you have a HOT lot of H4350?

 

[capnswervon]

Perhaps you have a HOT lot of H4350?

Good point on that. I recently opened up a jug of Varget that was producing speeds 70 fps over my previous jug. Lesson learned to always chrono new lots of powder as I was flying shots over 600 yard targets at a match.

The Capn'

 

[ArmyJerry]

Anyone using IMR 4350 with 140 gr SMK's?

 

[texote]

tagging for future load development

 

[Capt Academy]

Tagging for reference

 

[tylerw02]

Capn, that OAL can be killer. I had a few primers pierced and moved a little more off the lands and pressure went down significantly and speed went down, but not so drastic it was slow.

 

[capnswervon]

Per my original post, I am using Lapua Brass and I am not jammed. I was right off of marriage for the initial tests but now I am .010 out and seeing better results in the lower node.

Admittedly, the brass was probably weakened by the first ladder test that I took to 44gr and over 2900 fps. On the first firing of the Lapua brass they were not showing pressure signs including the primers so I did not think too much about it. However on subsequent reloads I started to see pressure signs and the insipid case separation occurred at 42.5gr. At that point I stopped and chucked the brass starting over.

I can get the velocity but no accuracy along with it. They were flying at 2800 fps at 41.5gr of powder but scattering like a shotgun. Most of the time, that means that it needs more powder to stabilize but then I get the pressure signs.

One other change to point out. I initially was resizing with a Hornady FL resizer with an expander ball. It seemed like I really needed to crank the die down to get any type of shoulder bump back when measured with my chamber gauge that is made from my barrel stub and reamer. My theory is that I was also over sizing the brass which let to additional stress and too much headspace coupled with hotter loads.

I just received my Whidden FL resizer and it is about as close the the custom dies I had made for my 308 chamber as you can get. It does not use an expander ball and resizes just enough to get it done.

I am most likely going to go back to the 41-41.5 range again with brass that has not been stressed and work out of the lands .010 and see what happens.



The Capn'

Update:

Per my post above, I went back and worked in the 41-42.5 range running in the 2780~2850fps and once again had no luck with a consistent load. I have had one or two groups that come together nicely but when I go back to confirm with another batch of the same exact load they do not perform the same.

I have just run a test with 140 Amax as well and they were even worse. I have also swapped the rifle into my other AICS 1.5 that is a proven chassis from my 308 rifle and the results were the same.

Is it possible that I have a 260 that will not shoot 140 class projectiles with H4350 at any kind of speed? Am I doomed to have a 260 that only performs in the velocity range of 2600-2650? Or am I missing something else?

Would you think that switching to 4831sc or Varget might solve my problem?

At this point, I have almost 500 rounds on this rifle and still do not have a load that I can use. Getting frustrated.

The Capn'

 

[BoilerUP]

Varget should shoot with with 140s, but 100-120fps slower than H4350.

Give RL17 a whirl too...

 

[One-Eyed Jack]

Capnswervon, here's my advice at this point: Find, borrow or buy a borescope and check for carbon buildup within several inches of the chamber throat. If you see any crud, get it out of there. I had a very accurate 223Rem Blaser LRS-1 whose accuracy degraded and left me scratching my head no matter how careful I was with my reloads. The problem turned out to be a carbon ring buildup that I didn't know about. So, have a good look with a borescope before you jump off a cliff.

 

[Sargesniper]

Update:

Per my post above, I went back and worked in the 41-42.5 range running in the 2780~2850fps and once again had no luck with a consistent load. I have had one or two groups that come together nicely but when I go back to confirm with another batch of the same exact load they do not perform the same.

I have just run a test with 140 Amax as well and they were even worse. I have also swapped the rifle into my other AICS 1.5 that is a proven chassis from my 308 rifle and the results were the same.

Is it possible that I have a 260 that will not shoot 140 class projectiles with H4350 at any kind of speed? Am I doomed to have a 260 that only performs in the velocity range of 2600-2650? Or am I missing something else?

Would you think that switching to 4831sc or Varget might solve my problem?

At this point, I have almost 500 rounds on this rifle and still do not have a load that I can use. Getting frustrated.

The Capn'

Try changing to the 139 gr. Lapua Scenar with 46.3 gr. H-4831sc. This load gives me 1/2"-1/4" groups with 2800+ fps. It works just as well in other .260's i know of. ............ SEMPER FI!

 

[capnswervon]

Capnswervon, here's my advice at this point: Find, borrow or buy a borescope and check for carbon buildup within several inches of the chamber throat. If you see any crud, get it out of there. I had a very accurate 223Rem Blaser LRS-1 whose accuracy degraded and left me scratching my head no matter how careful I was with my reloads. The problem turned out to be a carbon ring buildup that I didn't know about. So, have a good look with a borescope before you jump off a cliff.

One Eyed Jack,
Thanks for the input. I will take a look in there, however, I am one of the people that believe in still cleaning my rifle. I spend time in the neck area with a brush as well as use Isso every 2-300 rounds to keep my bore slick as hell. My gunsmith is a decorated benchrest shooter and would crap himself if I did not take proper care of my bore. I have been doing the same cleaning on my custom 308 and have had nothing but fantastic results. With that being said, I have tested similar loads with a clean bore as well as with a fouled one as I am aware that some guns like it a bit dirty.

I am now leaning towards an issue with the contact surface between surgeon reciever and chassis. I will let you know if that yields something.

The Capn'

 

[One-Eyed Jack]

Try changing to the 139 gr. Lapua Scenar with 46.3 gr. H-4831sc. This load gives me 1/2"-1/4" groups with 2800+ fps. It works just as well in other .260's i know of. ............ SEMPER FI!

That's close to what I'm shooting (47.0gr H4831SC), but I'd like to know what brass you're using (I use R-P) as well as the COAL (mine is 2.810") and primer type (I use Federal 210 or 210M).

 

[Sako man]

Ok here are my .260 questions. I would like to re barrel my .308 to a .260. I normally shoot out past 1000. I hear that .260 will be better than .308 at that distance.

1. anyone shooting .260 out past 1k, what do you think of the performance?

2. anyone using 139gr Scenars and Varget combo? I have lots of Varget and want to use it up.

Thanks!

 

[8nbait]

One Eyed Jack,
Thanks for the input. I will take a look in there, however, I am one of the people that believe in still cleaning my rifle. I spend time in the neck area with a brush as well as use Isso every 2-300 rounds to keep my bore slick as hell. My gunsmith is a decorated benchrest shooter and would crap himself if I did not take proper care of my bore. I have been doing the same cleaning on my custom 308 and have had nothing but fantastic results. With that being said, I have tested similar loads with a clean bore as well as with a fouled one as I am aware that some guns like it a bit dirty.

I am now leaning towards an issue with the contact surface between surgeon reciever and chassis. I will let you know if that yields something.

The Capn'

I went through the exact same thing, switched to varget and problem solved. May or may not work for you but I am a believer.

 

[BoilerUP]

Varget should provide good accuracy, but lower velocities than H4350 to the tune of 100-120fps.

I think AMU's Sheri Gallegher has won comps with 38gr Varget and 142SMk...but work up.

39.3gr in RP brass with a 123gr Amax provides 2938fps in my 26" 1:8 barrel. There might be a higher node, but this just works.

 

[Sargesniper]

That's close to what I'm shooting (47.0gr H4831SC), but I'd like to know what brass you're using (I use R-P) as well as the COAL (mine is 2.810") and primer type (I use Federal 210 or 210M).

Mr. Jack, I use Win. .243 Brass and either Fed./M or CCI BR2. I am jumping 12 thou. on the Scenar. Groups well but the velocity is a little slow for this Barrel but it shoots well enough as is. You are pushing a little over my load. Try backing down to my load and see if it comes together for you. If this does not work for you,load 43.5 gr. of H-4350. This seems to be a popular load for the .260 with many shooters. Hope you find the right load for yours. ........ SEMPER FI!

 

[Sargesniper]

Update:

Per my post above, I went back and worked in the 41-42.5 range running in the 2780~2850fps and once again had no luck with a consistent load. I have had one or two groups that come together nicely but when I go back to confirm with another batch of the same exact load they do not perform the same.

I have just run a test with 140 Amax as well and they were even worse. I have also swapped the rifle into my other AICS 1.5 that is a proven chassis from my 308 rifle and the results were the same.

Is it possible that I have a 260 that will not shoot 140 class projectiles with H4350 at any kind of speed? Am I doomed to have a 260 that only performs in the velocity range of 2600-2650? Or am I missing something else?

Would you think that switching to 4831sc or Varget might solve my problem?

At this point, I have almost 500 rounds on this rifle and still do not have a load that I can use. Getting frustrated.

The Capn'

Capn,does your rifle shoot any bullet into a good group? What twist rate do you have? New or once fired brass? Is your scope a proven accurate one? There may be more than a bullet/ powder problem here. What other weight bullets have you tried? I know how frustrating it can be,but if you start eliminating things one at a time you will solve the problem. ............... SEMPER FI!

 

[8nbait]

Varget should provide good accuracy, but lower velocities than H4350 to the tune of 100-120fps.

I think AMU's Sheri Gallegher has won comps with 38gr Varget and 142SMk...but work up.
39.3gr in RP brass with a 123gr Amax provides 2938fps in my 26" 1:8 barrel. There might be a higher node, but this just works.

I need 40.5 to get that speed out of 25" barrel but I haven't had it out past 400 yards yet to verify with drops.

 

[One-Eyed Jack]

Mr. Jack, I use Win. .243 Brass and either Fed./M or CCI BR2. I am jumping 12 thou. on the Scenar. Groups well but the velocity is a little slow for this Barrel but it shoots well enough as is. You are pushing a little over my load. Try backing down to my load and see if it comes together for you. If this does not work for you,load 43.5 gr. of H-4350. This seems to be a popular load for the .260 with many shooters. Hope you find the right load for yours. ........ SEMPER FI!

I'm already at an accurate load with R-P brass, no need to change anything. However, if I can't find any more R-P brass and have to use Lapua then I will have to adjust my powder load. Since you're not using Lapua brass, your load data won't help me much, but thanks for posting the info.

 

[Black-X]

My current load (in development) for my AI AE Mk III with a .260 AW barrel is:

142 SMK
Lapua Brass
210M Primer
42.6gr H4350
2.240 to the OGIVE

2.270-2.260 was making .5 groups, then .9 groups the next. Backed down 10thou at a time to 2.240 this evening and shot (2) .5moa groups. Keeping my fingers crossed it'll at least hold that or get it tweaked a little more.

The .260 is THE HARDEST round I've had to load for bar none. Seems odd since my 6.5 Creedmoor AW barrel would shoot .3-.5 just about every time and load development was fairly quick.

 

[capnswervon]

Capn,does your rifle shoot any bullet into a good group? What twist rate do you have? New or once fired brass? Is your scope a proven accurate one? There may be more than a bullet/ powder problem here. What other weight bullets have you tried? I know how frustrating it can be,but if you start eliminating things one at a time you will solve the problem. ............... SEMPER FI!

I am picking up what you are laying down. On Sunday I swapped the action into my other AICS which has been lights out with the 308 that has lived in it the past year. The results were the same. Tonight I took the Steiner off and swapped on my Mk4 LR/T from my DMR gun but I ran out of light before I could really try it out. That will be my Thursday AM test.

I have tried 142smk's 140 Amax's and 120 smk's.

The barrel is a 1:8" Hart

This brass is well fire formed and in great shape.

I have had a few nice groups but the next group at the same load will open up like nobody's business. There might be a deeper issue here.

The Capn'

 

[seanhagerty]

38gr of varget with 142smk's works for me too!! I have shot 3 and 4 inch groups at 700 yards with that load.