Help with a .260 load

[BP_Shooter]

I hope I can get some input..Here is what I got
Rem 700 SPS 260rem 24" barrel 1x8 twist (in an element chassis)
using Accurate 4350, fed 210, new lapua 260 brass, 140gr Hornady SST 2.80 coal

43.0gr AV 2600 fps SD 15 group size .25" (when I do my part...)
43.8gr AV 2643 fps SD 7 group size 1.5"
44.0gr AV 2627 fps SD 20 group size 1.5"

I didn't have any pressure signs. Is it just me or does this seem slow? any advice would be greatly appreciated.

 

[Steel head]

It does.
Could just be a slow barrel of chrony issues.

 

[Sako man]

You want to get .260 going over 2700 fps then your good. Your obviously going to have to up the charge. That said I use Varget 37.8 grain and get 2725 with a 24" barrel.

Try a different bottle of powder, you may have some moisture in yours or a bad batch. Has it been sitting in the hopper for a while?

 

[0311@LAR]

Switch to H4350 in the 42 grain area and you will be good to go.

 

[FALex]

Those velocities appear very slow. The Accurate 4350 has a faster burn rate when compared to IMR and H4350. My 43gr load of H4350 has 139gr Scenars going at about 2880 out of my 24" barrel.

OP - I'd go stab a plate or piece of paper out at 600 and shoot those same loads. See if your 2600+ is really 2600+.

 

[LoanHarvey]

Tag for follow up info

 

[BP_Shooter]

FALex

I thought about that, I have a shooter app that will adjust velocities according to mils used vs mils calculated. Just like the Atrag software.
I did test shoot it 2 different times on 2 different ProChronys and they came out the same. So I thought it might be something else.
I didnt think there was much difference between Accurate 4350 and H4350?
I know it isn't temp sensitive, I even tested in the morning when it was 75 and then in the afternoon when it was 102 with no change.

Accurate's website say this: 140 Sierra SBT GK 43.5 2743fps/ 140 nosler partition 42.5 2733
Hornady shows: 41.7 @ 2700

Do you folks think its the powder? Its new, I just recieved 8lbs of it on th 27th

 

[BoilerUP]

It'll speed up after a couple hundred rounds.

As mentioned, H4350 will give better velocity as will RL17.

 

[BP_Shooter]

It'll speed up after a couple hundred rounds.

As mentioned, H4350 will give better velocity as will RL17.

Why would it speed up? so far I've shot at least 70 rounds during testing. I don't understand what would change with the powder after a couple hundred rounds?
I was going to see if one of the local stores had H4350. Think I should look for RL17? I was thinking maybe my gun doesn't like the 4350 powders or maybe I got a bad batch of 4350....

it was very accurate with 43gr. It just seems like a waste to have 140's loaded with 43gr and getting 2592-2609 fps...

not to mention 0.8 grains more only gave me 43 more fps, and then when I tried 44grs it actually went down to 2627

 

[BoilerUP]

The powder doesn't change, the barrel breaks in a bit and speeds pick up a little.

Also, what kind of chronograph are you using?

 

[BP_Shooter]

Used 2 different pro chrony. At first I thought the chrono was messed up, but both got the same results... My biggest concern was that I worked up to 44grs and never did more than 2656, in fact speed went down going from 43.8 - 44.0

 

[mjh30]

OP, with regards to 4350 powders, Accurate, IMR and Hodgon are similar in burn velocity, but in my opinion the similarity ends there, I believe right now they are being manufactured on 3 separate continents. The go to powder for most of us shooting 6.5's would be H4350 and H4831sc. I have a Friend using AA4350 in a f-class rifle purely because it gives him the best accuracy, and the fact that the pipe on his rifle is about 6 or 8 inches longer than most of us are running, so his velocity is were he wants it to be. If you are stuck using aa4350, up your load safely to increase velocity as long as accuracy doesn't drop off.

 

[BP_Shooter]

I found 1lb h4350, loading up test rounds now..

 

[Steel head]

I found 1lb h4350, loading up test rounds now..

H4350 REALLY does well in my 260.
42and 43.9 are my nodes with Hornady 140BTHP's and a 26" barrel.

H4350 has to work a bit harder to match R17 speeds but group size was cut in half!

 

[BP_Shooter]

well it was the powder!
42.0gr 2706 ES-50 SD-19
42.5gr 2729 ES 28 SD-11
43.0gr 2764 ES-29 SD-12 (group was 1.5-2)
43.5gr 2773 ES 17 SD 7 (group was 1.5-2")

thats amazing considering with 43.8 of accurate I was getting 2627. well now to fine tune. Thanks for everyones input. hopefully the A4350 will work with lighter bullets. any other advice please let me know...

 

[Steel head]

That was fast!

Your speeds are close to mine

42=2730
43.9=2840
26 in barrel

 

[DPMSLR308]

I had to go to 42.5 grains of H4350 in a 26" Bartlein 1-8 barrel to get 2768 fps.

 

[BP_Shooter]

What bullet?

 

[BP_Shooter]

I think I'm going to work from 42.5-43.9 by 0.2 and see what nodes I can find. I think I'm going to pick up some 123 or 129's and see how they like the accurate 4350.

 

[DieselWSM]

H4350 @ 44.2 w/ 139 scenar yielded 2880 in a 24" for me

 

[ZombieMonkey]

Seems really slow, I'm seeing right around 2815 fps out of a 24" barrel with 43.5 gr of A4350 in my AI when pushing the 139gr Scenar. (100 degree temps). My buddy is seeing fairly similar speeds out of a 23" barrel on his rifle from PCR and the same load data. I've got them loaded a bit long as they are 0.015 off the lands.

I tested up into the 44-44.5 territory before I called it quits, only saw very mild flattening of the primers in the Lapua cases, no other signs. I spent very little time above 44 though as that's a bit spicy for my liking.

 

[sib1948]

Saw some one pounders of H4350 last week at Bruno's last week and still have a few pounds in my garage, if you're interested!

PS-my son and I will be at Rio on the HP range around 8-9 tomorrow morning.

 

[BP_Shooter]

well now if it I can get it to group...
testing today went..
42.7gr
AV 2736 ES-28 SD12

42.9gr
AV 2754 ES 40 SD16

43.1gr
AV 2768 ES34 SD12

43.3gr
AV2783 ES12 SD4

43.7gr
AV2797 ES35 SD13

43.9gr
AV2799 ES41 SD 20

nothing seems to want to group. I'm wondering if I changed seating depth? I'm at 2.800 maybe go to 2.820?

 

[BP_Shooter]

well I've tried 2.800, 2.820, 2.830 and 2.840 and no luck with groups. Very frustrating, the accurate powder was slow but had really good groups, the h4350 is fast but won't group worth crap! I'm at a loss, any ideas?

 

[LoanHarvey]

Try RL-19!

 

[BP_Shooter]

Recommendations on starting and max loads? SST 140.0gr