Reading pressure signs on Lapua brass (.260 Rem, RL17)

[mclark]

Hi all, I'm relatively new to precision long range shooting and reloading but have been hunting a long time. I'm pretty OCD and I think I'm doing a thorough job with my prep and loading but I still have lots to learn.

This fall I picked up a new Tikka Sporter in .260 Rem. with a 20" barrel.
Ammo components are as follows: New Lapua brass, Lapua 139 Scenar bullets, RL17 powder, CCI standard large rifle primers.

I'm loading at .020 jump with puts my loaded rounds at about 2.98 O.A.L, 3.348 as measured with a Sinclair hex comparator.

The only similar load on the Alliant web site was for 41 grains of RL17 with a Speer bullet, loaded to spec. length. I loaded 10 break-in rounds, starting about 10% below that and worked up to 42 grains in my first string, seeing and feeling no pressure signs. Temps were 45-50 degrees.

I then loaded 10 more, up to 45 grains in .5 grain increments. I shot those at lunch today - 45 degrees, ammo kept in my jacket pocket to stay out of the chilly breeze. Still no real pressure signs.

These are the slight changes in case dimensions I'm getting.

Case head measurement, taken at base just ahead of the rebate:
new, unfired Lapua: .469
40 Grains and up: .470
42 Grains - 44 grains: .471
44.5 - 45 grains: .472 with a more visible line of expansion just above the rebate

Case length:
No noticeable change, varies by about .002 in this lot of brass but 90% are within .001

Primers:
The 44. 5 and 45 grain loads look like the primers are very slightly flattening, just a small decrease in the side to base radius on the cup.


So..... 45 grains sounds like a hot RL17 load but I also have more case capacity than spec. loads so I knew pressures would be lower.

I'm looking for advice on reading pressure signs. The great articles on the Rifleman's Journal blog and others I have found seem to say that as soon as you see any slight pressure marks from the ejector or extractor, you are over pressure and should back down. I'm not seeing anything at all.
My thought is that I'll load up another batch up to 48 grains and look for pressure signs just because I'd like to know, but is this foolish?
Any advice with Lapua brass specifically? Does it show those signs at normal high pressures or do you have to get way too high to see them?
Anything I'm missing?

I don't have a chronograph yet so no velocity data, sorry. And I know I'll have to re-test when I'm shooting at 80 plus this summer......

Thanks for the help,

Matt

ps. I posted this question on accurate shooter as well but wanted to get as much info and thoughts as possible.

 

[high right]

I shoot a 260 as well. I tried about 10 rounds with rl17 and had to toss the brass. It was way to hot for mine, plus here in Co.
it can be 35* in the morning and 80* in the afternoon. Not a good powder for temp. swings.
could be your brass too. earlier lots of lapua had loose pockets.
I got a buddy that swears by it, he also replaces his barrel after about 1700 rounds.
h4350 or h4831sc may be your answer

 

[bkw1911]

You are loading way longer than spec so you can get away with a bit more. My dads 260 with lapua brass and h1000 with 140 vlds at almost 3.00" he pushed a few grains over max listed. If you work up in .5gr increments youll see a brighter ejector mark and the bolt lift can start to stick. I would stop when youre getting there and then go a half gr back as your safe max. Depending how warm it gets where you are, with rl 17 you might back it off another 1-1.5gr from where you saw greater pressure signs. In az a max load developed in the winter can be deadly in the summer

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[bjay]

You are loading way longer than spec so you can get away with a bit more. My dads 260 with lapua brass and h1000 with 140 vlds at almost 3.00" he pushed a few grains over max listed. If you work up in .5gr increments youll see a brighter ejector mark and the bolt lift can start to stick. I would stop when youre getting there and then go a half gr back as your safe max. Depending how warm it gets where you are, with rl 17 you might back it off another 1-1.5gr from where you saw greater pressure signs. In az a max load developed in the winter can be deadly in the summer

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What about on short magnum cal.. 7 saum RL25 light ehector marks on 62gr 61.40 is accurate very faint ejector marks should i bring it down to 61.00 where no ejector marks anymore? I live in hawaii we our weather dont dramaticaly shift it stays 67-78 maybe 80 on summer

 

[bkw1911]

Alot of guys still run loads a little over pressured that have ejector marks. If you want the velocity and dont care about the brass life or barrel life then go for it. Ive run several loads that flatten primers a bit but dont leave me with a sticky bolt (unless I shoot a 10rd string). Thats some nice weather to be having there. We peak at almost 120 so if your rounds and barrel are sitting in direct sun it can get pretty scary quick. I dont think you have too much to worry about

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[bjay]

Alot of guys still run loads a little over pressured that have ejector marks. If you want the velocity and dont care about the brass life or barrel life then go for it. Ive run several loads that flatten primers a bit but dont leave me with a sticky bolt (unless I shoot a 10rd string). Thats some nice weather to be having there. We peak at almost 120 so if your rounds and barrel are sitting in direct sun it can get pretty scary quick. I dont think you have too much to worry about

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Its a expensive built saum with fluted krieger barrel using expensive norma brass lol..its pushing 3140fps 61.40 RL25 in short action.180hybrids
Will this light ejector marks and FPS will toast my barrel/brass soon? How far will i get on barrel life.its tge rifle on AICS AX stock

j

 

[bkw1911]

I unfortunately don't know the 7 saum well enough but I know guys get good groups and velocity with some of the alliant powders but shy away because they burn there barrels faster. I know with the 6.5 saum to get close to 3500-4k rounds of life guys run them pretty mild

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[bjay]

I unfortunately don't know the 7 saum well enough but I know guys get good groups and velocity with some of the alliant powders but shy away because they burn there barrels faster. I know with the 6.5 saum to get close to 3500-4k rounds of life guys run them pretty mild

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When we say mild load what fps are we talking about..

 

[bkw1911]

The 6.5 saum will push a 140 in the 3300fps range and alot of guys run them at 3100ish. Mainly due to velocity restrictions at matches but increases the barrel life significantly. Its all about the pressure though so im not sure what that would be at for the 7. Id read some barrel life threads and some of the 6.5 saum threads

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[milo 2.0]

I posted earlier today in your thread on 6br, got lost.
I'm in the process of switching to RL 17 in my 6.5x47's. I've noticed that pressures spike hard and fast. So coupled with Lapua brass, pressure is hard to see, pierced primers was my only indicator.

 

[mclark]

Thanks Milo, I think I'll stop at 43.5 grains for now and watch my case dims. over successive firings. I'm going to concentrate on finding an accuracy node in that range and below, no need to burn my barrel and brass up.

Matt

 

[bjay]

Thanks Milo, I think I'll stop at 43.5 grains for now and watch my case dims. over successive firings. I'm going to concentrate on finding an accuracy node in that range and below, no need to burn my barrel and brass up.

Matt

i also have 260 in bartlein 24" using h4350 42.8 with 2860 fps i tried all the way close to 44gr and get close to 3000fps this my second 260, ive noticed that both of them not too accurate when pushing it too fast..im not sure if its the powder so you will proly get better luck with rl17..lat time i tried it to 500yd i was .263 moa..accuracy and barrel life first before fps << thats me

 

[high right]

I unfortunately don't know the 7 saum well enough but I know guys get good groups and velocity with some of the alliant powders but shy away because they burn there barrels faster. I know with the 6.5 saum to get close to 3500-4k rounds of life guys run them pretty mild

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I shoot a 7 saum with the 180 hybrids too. I think the magic is the powder h-1000, low pressure and getting 2920

 

[milo 2.0]

I shoot a 7 saum with the 180 hybrids too. I think the magic is the powder h-1000, low pressure and getting 2920

Do you use Quickload, or how do come to the conclusion you're low pressure? I'm on my fifth 7 saum, haven't tested H1000 in the last two, but my old data looked like this;

H1000
60.0gr-2712fps
61.0gr-2736fps
62.0gr-2786fps
I stopped there, either ejector marks, or stiff bolt. I'm pretty sure that was a nitrided barrel with moly bullets.

 

[high right]

Im at 63 grains in a 27" with no pressure signs

 

[high right]

Do you use Quickload, or how do come to the conclusion you're low pressure? I'm on my fifth 7 saum, haven't tested H1000 in the last two, but my old data looked like this;

H1000
60.0gr-2712fps
61.0gr-2736fps
62.0gr-2786fps
I stopped there, either ejector marks, or stiff bolt. I'm pretty sure that was a nitrided barrel with moly bullets.

You shoot with Kevin?

 

[milo 2.0]

Yes I do!

 

[bjay]

I shoot a 7 saum with the 180 hybrids too. I think the magic is the powder h-1000, low pressure and getting 2920

Not really.. if you have it in long action maybe? Or barrel that is shorter that 27.. my 30" saum7mm. cant even get close to 2900 before ejector marks and stiff bolt started.. 62grh1000 180 hybrids oal 2.955 with the same set up RL25 lesss than 62gr i can get 3100 with very faint ehector marks

 

[high right]

I am long baby!

 

[milo 2.0]

Not really.. if you have it in long action maybe? Or barrel that is shorter that 27.. my 30" saum7mm. cant even get close to 2900 before ejector marks and stiff bolt started.. 62grh1000 180 hybrids oal 2.955 with the same set up RL25 lesss than 62gr i can get 3100 with very faint ehector marks

bjay,
high right and I are at quite different altitude levels than you, it can't be the same. To compare, 67gr of RL25 gives me 2965 out of a 28" tube, I could go to 68, but I'm sick of fighting seating depth with compressed loads. My last 25" barrel, I could get 3035 with RL25, but never did shoot the load, just checked it.

 

[high right]

hey milo, I shoot with Kevin quite a bit, Great guy! I hear about him shooting with you guys when he goes up there. sounds like he might bail on his saum!
I'm keeping mine! I haven't put too many down the tube, but I like it.
I did mine on a Big Horn long action cause of the seating issue. real happy so far.

 

[milo 2.0]

hey milo, I shoot with Kevin quite a bit, Great guy! I hear about him shooting with you guys when he goes up there. sounds like he might bail on his saum!
I'm keeping mine! I haven't put too many down the tube, but I like it.
I did mine on a Big Horn long action cause of the seating issue. real happy so far.

That's funny, when he was here last, he liked it! Not much of a comp gun though.

 

[high right]

Call him a quitter! that gets him fired up

 

[bjay]

bjay,
high right and I are at quite different altitude levels than you, it can't be the same. To compare, 67gr of RL25 gives me 2965 out of a 28" tube, I could go to 68, but I'm sick of fighting seating depth with compressed loads. My last 25" barrel, I could get 3035 with RL25, but never did shoot the load, just checked it.

The last tyme we spoke on 7mm saun liad thread i told you i was having hard time find rl25.i also tried experiment h1000 and 4831sc dint like their presure before geting to the fps that i wanted.. people warned me from using rl25 being temp sensitive.. but like you said our sea level is diff.. i guess living in hawaii not so bad after all not worying about temp on using rl25 powder our temp stays 67-80 all yr long... im shooting this afternoon let u know my findings..milo cab u confirm my fps by using distance .if m saum zeroed at 100yd and i dialed 4.50moa to be on bullseye ata 407 yard how fast do you think my fps..

 

[milo 2.0]

The last tyme we spoke on 7mm saun liad thread i told you i was having hard time find rl25.i also tried experiment h1000 and 4831sc dint like their presure before geting to the fps that i wanted.. people warned me from using rl25 being temp sensitive.. but like you said our sea level is diff.. i guess living in hawaii not so bad after all not worying about temp on using rl25 powder our temp stays 67-80 all yr long... im shooting this afternoon let u know my findings..milo cab u confirm my fps by using distance .if m saum zeroed at 100yd and i dialed 4.50moa to be on bullseye ata 407 yard how fast do you think my fps..

I'd have to say you're close or over the 3100 mark, good speed, my last 4 saums have been under 3000, 1st one ran 3160, ah, the good ole days!

 

[bjay]

I'd have to say you're close or over the 3100 mark, good speed, my last 4 saums have been under 3000, 1st one ran 3160, ah, the good ole days!

When i was braking in barrel i tried this combo up to 62gr and i could only get 2950 i decuded to keep this load and after litle over hundrend rds od load developing i decided to get back to the same load 61.40 try hit 400yd 10" plate..missed! Then a spoter said high by 1moa so from 5.5 down to 4.5 moa i put 4 bullet on the bullseye.does this meah my barrel broken in after 115rds and now i think im goin 3140fps? Will this fps stay? Miloshould i slow it down a bit with this load i got 1.08" 5 shot at 407 yard. Almost quarter moa should i stay there or slow it down save brass and barrel.or is this concieder as mild load.very faint ejector mark

 

[bjay]

This of corz with 180 hybrids fed 215m primer norma 300saum brass necked down

 

[milo 2.0]

Bjay, any mark on the case head is pressure, unless your bolt face is marred somehow, highly unlikely.
Velocity is up to you, any gun over 3000 fps is going to have shorter barrel life than one with less speed. A choice???
Myself, I'd hammer the friggen thing, kick some butt, especially past 1K, that extra 150fps makes shit happen!
Yes, a barrel can, and some of mine have increased in speed, usually after 60-100 rounds.

 

[bjay]

Bjay, any mark on the case head is pressure, unless your bolt face is marred somehow, highly unlikely.
Velocity is up to you, any gun over 3000 fps is going to have shorter barrel life than one with less speed. A choice???
Myself, I'd hammer the friggen thing, kick some butt, especially past 1K, that extra 150fps makes shit happen!
Yes, a barrel can, and some of mine have increased in speed, usually after 60-100 rounds.

i loaded 61gr and going to try them in litle while if accuracy still there with 3050-3100..i might stay there specialy if no ejector marks at all.. ty for response milo, short but sweet...hmm i wonder what barrel CT will 3100fps give me? hows your saum any more result wanna share?

 

[milo 2.0]

BJ,
With all my saums, except for this last one, I started with the Berger 175xld, one hell of a bullet, and you could buy them cheap. I'd shoot till I had throat erosion and accuracy dwindled, then switch to the hybrid. My first gun, a 30" McGowen was the fast one, throat failed at 800, switched at about 950 after some floundering, at 1900, cut 2 1/2' off, and set the barrel back, it came back even shooting better, at 2900 I rebarreled, but it was still shooting, just wanted to reconfigure the package, stock, etc. I put a 25" Krieger heavy palma on it, McMillan adj hunter stock, the gun just sucked, accurate as all get out, but so light spotting your shot at under 700 yards was impossible. At 400 rds, I restocked this year again with 28" Krieger HV, HS pst 025 stock, right now it's rocking 3025 with hybrids, 67.5gr of N570.

My second was a 24" Brux, accurate as hell, but slow, just over 2900, barrel was nitrided, at about 1750 it wouldn't shoot after it warmed up, so it got a new barrel. It's supporting a 27 1/2" Brux again. Running Rl25, it's pushing 2965, had a 3rd round hit at 2073 on Monday.

As for rd count, I think that is just the luck of the draw, my nitided barrel should have went 2500, it was a disappointment! The McGowen went forever, and it only cost 150.00, go figure. With the hybrid, they'll still shoot through throat issues, you'll know when the rifling goes!

 

[bjay]

BJ,
With all my saums, except for this last one, I started with the Berger 175xld, one hell of a bullet, and you could buy them cheap. I'd shoot till I had throat erosion and accuracy dwindled, then switch to the hybrid. My first gun, a 30" McGowen was the fast one, throat failed at 800, switched at about 950 after some floundering, at 1900, cut 2 1/2' off, and set the barrel back, it came back even shooting better, at 2900 I rebarreled, but it was still shooting, just wanted to reconfigure the package, stock, etc. I put a 25" Krieger heavy palma on it, McMillan adj hunter stock, the gun just sucked, accurate as all get out, but so light spotting your shot at under 700 yards was impossible. At 400 rds, I restocked this year again with 28" Krieger HV, HS pst 025 stock, right now it's rocking 3025 with hybrids, 67.5gr of N570.

My second was a 24" Brux, accurate as hell, but slow, just over 2900, barrel was nitrided, at about 1750 it wouldn't shoot after it warmed up, so it got a new barrel. It's supporting a 27 1/2" Brux again. Running Rl25, it's pushing 2965, had a 3rd round hit at 2073 on Monday.

As for rd count, I think that is just the luck of the draw, my nitided barrel should have went 2500, it was a disappointment! The McGowen went forever, and it only cost 150.00, go figure. With the hybrid, they'll still shoot through throat issues, you'll know when the rifling goes!

im guessing all these were on SA receiver? im thinking of ordering extra barrel from bartlein 1:8.75 twist..but its not going to be HV contour and 30" anymore25 or maybe 26" what would be a good weight barrel rem varmint? or med palma? is m24 litle to much weight..im planing to use this for hunting aswell..maybe sell my AX and get go back to A5..or maybe just build another saum on diff configuration..