Is this load too hot?

[31B]

I have a new 6.5x47L. After looking at other info on line, it looks like my load might be too hot for this cartridge. Here are the facts:

26" Krieger 5R 1:8 twist
130 Grn JLK
205M primer
Viht N150

38.5 grains averaged 2897 FPS for 11 rounds.

38.8 grains averaged 3027 FPS for 15 rounds.

Some of the Brass had light ejector marks on the head. Most of the primers were slightly cratered. "Heavy" bolt lift is kind of subjective. It was stiffer to lift the bolt on a fired cartridge as opposed to an empty chamber but I wouldn't call it "heavy."

Does this sound like these loads are too hot? Any opinions from those with more experience w/ a 6.5Lapua than I would be greatly appreciated.

TIA

Mitch

 

[Johnboy]

by not knowing your case over all length its hard to say.but by useing the SAAMI case length its at the top for the 38.8 load.so you are at the top for that charge.just be careful.

 

[fdshuster]

An increase of 130 fps ( 3027-2897= 130) with a 3/10 of a grain increase in powder?

 

[31B]

Johnboy,

The case length is 1.84". It is virgin brass and I have not trimmed it. The bullet is .010" off of the lands.

fdshuster,

Good point. I'm wondering if my chronograph is operating properly. It's a Shooting Chrony that I've had for at least 10 years. I suppose it's possible that my scale is off as well, but I balance it w/ "check weights" before every reloading session.

Any insight is welcome.

TIA

Mitch

 

[Keith Glasscock]

Any ejector mark, however slight, is cause to back off. Those are too hot for continued use!

I do go past slight ejector marks when looking at a new powder because those slight marks are hard to see at the bench, but sure enough, my match loads do not have ejector marks.

I'm also suspicious of your chronograph. My shooting chrony was seriously messed up and getting a good chrono (CED) helped me a lot in my load development.

 

[31B]

Busdriver,

You have a good point about backing off if there are ejector marks (regardless of the chrono numbers).

That said, something is not right. The extreme spread for the 2897 FPS avg. was 147. The extreme spread for 3027 FPS avg. was 78.

I'm wondering if my chrono is malfunctioning or if there is a problem w/ the powder. I've had the powder for about 2 1/2 years and just cracked the seal on it. I don't think it is my scale. Any thoughts anyone?

TIA

 

[Keith Glasscock]

If I were a betting man, and I am, I would bet it is the chrono. I had almost identical ES numbers with my Shooting Chrony for a load that grouped well all the way to 600 yards. Funny thing is, that same load had an ES of 15 when I shot it over my CED. BTW, my Chrony also read about 50-75 fps lower than the CED. Interestingly enough, JBM now makes sense for my loads out to really long ranges (1000 yards was within 1/2 MOA on the come-up).

I would take the lighter load (assuming it doesn't mark up the case heads) and shoot it over another chronograph. I think everyone should have a friend with an Oehler 35P. I just wish my friend was near by.

Best of luck.

 

[Shynloco]

Personally, I think the subjective evidence of pressure in the slight cratering, the harder than usual bolt opening and potentially the markings on the casing, are more important to consider than what the chrony is registering. And that with the bullet being set .010 off the lands. Theres a good chance your pressure would increase even more if the bullet were into the lands. Try not to forget, that each rifle is different and what may not show up as pressure in one rifle, may have adverse showing in others. If it were me, I'd back off some on the load and try again. Once the pressure signs quit (at the present bullet setting), then worry about what the chrony shows. Just my thoughts.

 

[TonyR]

Have you measured case head expansion, change in diameter inside the extraction groove?? I am usually seeing something less than 0.0005 inches or I can also start to see some of the other signs that have been discussed.

 

[31B]

Thanks for the input everyone. My plan is to back off of the load until no ejector marks or cratered primers. I'll try a new load this weekend and deal with my chrono too.

 

[Innovative]

31B .......

Most of the time "ejector" marks on the case head are caused by excessive chamber pressure. Some chambers will raise pressure much quicker than others. Those dents could also have been caused by not cleaning ALL of the case lube from your handloads or oil in your chamber. Here's a good article on reading pressure signs

http://www.larrywillis.com/pressure_signs.html​

 

[31B]

I reduced the load and here is the latest for N150:

38.2 grn
Avg: 2815 for 9 rounds
ES: 32


37.9 grn
Avg: 2806 for 12 rounds
ES 36

The other change is that I used a .286" NK bushing (Redding type S) for the previous loads and I used a .287" NK bushing for these loads. I'm still getting slight cratered primers and light ejector marks on some of the cases. Bolt lift did not feel "heavy" to me but it may to another.

After looking at Innovative's link, it appears that slight cratered primers is not necessarily a problem, generally speaking. After searching the forum it appears that a 6.5 Lapua is prone to some crated primers at pressures well below safe. The ejector marks still concern me and I like to get a little more velocity out of this.

So...I tried Hodgdon H4350 and I seated the bullets to magazine length, about .040" off of the lands. Good velocity and some loads show promise w/ group size. Very light primer crater and very light ejector marks on some. I'm going to try H4350 a little more and see where this goes.

I'm still a suspicious of my chrono but I don't have any access to another to compare.

Thank you everyone for your input. I appreciate the suggestions.

 

[BoydAllen]

Sometimes is a chamber is not bone dry, cases can show pressure signs that would otherwise not be there, because of the way that they are moved around during firing. How do you dry your chamber after cleaning, and what do you clean with?

The cratering can be simply a matter of firing pin fit.

I would suggest that you use a systematic load workup procedure, loading at the range. When I do this, I start out at a known safe load, with the bullets engaged in the rifling by an amount that seems to have worked well in the past, for bullets of that type. If I lack that information, I will usually start somewhere between .006 and .010 longer than touch. With that seating depth, FL sizing each time I load, with a precise shoulder bump, based on a case that has been fired with neck sizing only for 2-3 firings, until "headspace" has maxed out. From my known safe load, I would shoot one each, of .3 gr. increases until I felt the bolt lift change. At that point, I would stop, and record the temp. and humidity, and note the load. From that point I would look at the target that I shot the pressure test on to see if there was any range of trial loads that seemed to cluster, and do some testing at a load that was within that range. After that I would play with seating depth, changing the setting by .002 at a time, shooting two shots, as rapidly as possible (for the two shots) while paying close attention to my wind flags. If a seating depth looked promising, I would hold it constant and play with powder charge, .3 above and below. All of this is made mush easier and faster if you have everything for loading right by where you are shooting. Loading at home to work up loads is like walking instead of driving.

 

[KT]

you got pm.

KT

 

[mr45man]

<<<I suppose it's possible that my scale is off as well, but I balance it w/ "check weights" before every reloading session.>>>

Just to make you feel better about your scale:

Take a bullet in the weight range of your charge 35 or 40 grain 20 cal bullet,
mark it with a Sharpe and have the local Jewelry store weigh it.

Then you can check the scale during charging with a known weight in the range of your charge.
John H.

 

[BoilerUP]

Try a CCI primer and see if they still crater.

 

[31B]

KT

I got the PM. Thanks.

Boyd,

I recently started using Wipe Out / Patch Out (liquid). I use a bore mop to dry out the chamber. I suppose there could be some residue but I'm pretty careful about that. I take your point about reloading at the range but I'm not set up to be mobile.

I tried H4350 in a ladder test last Sunday and that looks promising (velocity & groups). I plan to refine that this weekend and I'll let you know how it goes. I do try to be methodical and take good notes. I plan to try the OCW method as well. I've never used OCW so I'm interested to see how it compares to a ladder.

I did change seating depth for the H4350 back to 2.8 COAL. I have not done that w/ N150. Maybe that would help. I wanted to make N150 work because I have 8 lbs of the stuff but at the end of the day if it doesn't work, then it doesn't' work. I'm not comfortable w/ jambing bullets into the lands.


mr45,
I have actual check weights marked at 20 and 10 grains that I check my scale with before each use. The check weights may be out of spec but since I use them each time I should be consistently out of spec...so I'm still a little suspicious of the Shooting Chrony.

BoilerUp,

I have some CCI primers but so far the 205M's and H4350 seem OK so far. I let you know after this weekend.

Thanks everone for the input. I appreciate the help.

Regards,
Mitch

 

[31B]

OK..so I tried Hodgdon H4350. Without getting into the details, my chrono got caught in out in the rain and is not working anymore so I have limited chrono numbers. (Time to buy a new chrono.)

I'm getting consistent groups and good velocity between 41.9 grns (Avg. 2853 fps) and 42.5 grns (Avg. 2926 fps). The bolt lift feels good but I'm still getting light ejector marks and light primer cratering. However, I'm getting the same (albeit a little lighter) at 38.5 grns (Avg. 2630 fps) through 41.9 grns. I doubt that that is anywhere near max pressure.

For those w/ more experience w/ the 6.5 Lapua, is it more prone to showing ejector marks? As I've posted earlier, a forum search shows that the 6.5 Lapua tends to primer crater at pressures well below max. I've searched further and some have experienced the ejector marks on virgin brass and then disappearing on the second firing. What gives?

I'm happy w/ what I'm getting at the charge range listed above but what is the consensus on the pressure? Is 41.9 to 42.5 too much for H4350?

TIA for the input.

Regards,

Mitch

 

[Innovative]

A picture of your bolt face showing the firing pin in the extended positon sure would help. I think you're too concerned about "cratered" primers. Pay more attention to the flat edge of the primers - like in the pictures of the article that I referenced above.

If you're still seeing NEW ejector dents that is a high pressure sign for sure.

 

[31B]

First of all, thanks everyone for all of the suggestions and info.

Long story short, I've tried 6 different powders and keep getting ejector marks, to one degree or another, from the starting powder charges to the max powder charges.

I would describe the ejector mark as a spot on the case head shinier than the rest. I cannot feel any ridges if I run my fingernail over it. The primer pockets are tight, the bolt lift does not feel "heavy" (but that is subjective), the edges of the primers are not sharp, and the cratering is not excessive. I'm coming to the conclusion that these shiny ejector marks are peculiar to my rifle even at starting powder charges.

Obviously, if I get more conspicuous pressure signs, I will back off the charge.

So I' going to go back to N150 (because I have 8lbs of it) and fine tune 36 to 38.5 grains.

Regards,
Mitch