6mm WSM Pic

[scope eye]

Yes after awhile there is little gain in speed, when you start reaching max pressure, instead of they energy pushing the bullet forward, they energy is deforming the case and primers, and other chaotic stuff that are going inside the case, I don't think I have shot a under max load in ten years, so I know this from experience.

Dean

[TC260]

maybe i missed something but why would a chrony be needed to indicate pressure signs?
regardless of what caused it a heavy bolt lift to me is a sign of pressure. so is a blown primer.
no doubt some brass will fail before others but that is still pressure with that particular brass.

A chronograph is useful because there's a strong correlation between velocity and pressure. Short of having actual pressure testing equipment, the best we can do is correlate velocity with data that is pressure tested. That's why reloading manuals include velocity with their data. Our specific numbers won't be exactly the same but it's a lot more information than just shooting blind until a round sticks. Usually with a wildcat there isn't pressure tested data to work from but using a chrony helps establish a baseline for the round. If for example velocities start spiking up or leveling off you know something's changing and there's some good information to work with to make decisions.

The point about the yield strength of brass was just that there's a difference between the safe working pressure of ammo and the pressure at which the brass starts to fail.

[yobuck]

[QUOTE=TC260;182444]A chronograph is useful because there's a strong correlation between velocity and pressure. Short of having actual pressure testing equipment, the best we can do is correlate velocity with data that is pressure tested. That's why reloading manuals include velocity with their data. Our specific numbers won't be exactly the same but it's a lot more information than just shooting blind until a round sticks. Usually with a wildcat there isn't pressure tested data to work from but using a chrony helps establish a baseline for the round. If for example velocities start spiking up or leveling off you know something's changing and there's some good information to work with to make decisions.

sure theres a strong corelation between velocity and pressure. pressure is what causes velocity.
the gun will tell you all you need to know about pressure and accuracy. most of us load and shoot for accuracy. max velocity is at least usually a secondary value. theres no doubt that at some point velocity gains taper off and adding more powder for the sake of velocity is pointless. that frankly is of little concern for average joe looking for a good load.
chances are what it told you today will be different tomorrow anyway.

[TC260]

Hmmmm, you agree with me about the relationship between pressure and velocity but are arguing against measuring velocity to estimate pressure? Whatever.

[jhelmuth]

There are so many casual shooters who have never used a chrono (and frankly are either intimidated by them or are just too cheap). But once they do and understand how it works to tell them more about their loading, they become big fans. I'm one of those myself (who became a big fan after finally breaking down and deciding that being cheap was expensive). I have saved money and time by having my chrony - and more importantly.... I've become better at handloading because I can "see" how my component choices (and techniques) impact my MV, ES, and SD.

Love my Chrony!

[bootsmcguire]

http://i747.photobucket.com/albums/xx111/bootsmcguire/ICONS%20and%20Forum%20Stuff/focus.gif (http://s747.photobucket.com/user/bootsmcguire/media/ICONS%20and%20Forum%20Stuff/focus.gif.html)http://i747.photobucket.com/albums/xx111/bootsmcguire/ICONS%20and%20Forum%20Stuff/thumb_zps1839369f.gif (http://s747.photobucket.com/user/bootsmcguire/media/ICONS%20and%20Forum%20Stuff/thumb_zps1839369f.gif.html)


Well I got just a bit of time to run some bullets over the chrony. 105 A-Max, H1000, Rem 9 1/2M, seated out to the lands in a 28" 1-9" twist barrel.
61.0gr delivered an average of 3299FPS with a SD of 7.2
63.0gr delivered an average of 3334FPS with a SD of 15.1
64.0gr delivered an average of 3462FPS with a SD of 7.0

Still no signs of pressure. Bolt opens easy and brass and primers look great. Didn't get to record any group sizes as I really didn't try for groups due to a very short time schedual and a 25-30mph cross wind today.

[okie2]

Smokin! That should be crazy fast!
And here I thought I was going big when I built a 6mmAckley pushing a 75gr at 3850fps! That thing will probably push those 105's at that speed. Lol
Let us know how it goes!
A 6-06 AI will get 4200 fps with 70 grainer

[scope eye]

A 6-06 AI will get 4200 fps with 70 grainer

I can attest to that.

Dean

[bootsmcguire]

I am really hoping to get the 105's up around 3650 to 3750. Going to keep going up and see where it gets me. Hopefully this weekend I can slip up to the range again and work up a few more grains higher.

[yorketransport]

I am really hoping to get the 105's up around 3650 to 3750. Going to keep going up and see where it gets me. Hopefully this weekend I can slip up to the range again and work up a few more grains higher.

That sounds more like it. Your 64gr charge is moving pretty fast, but not as quick as I expected. Have you tried anything slower than H1000?

Andrew

[bootsmcguire]

Well I didn't make it ot the range last week, cross my fingers for this week.

H1000 is the only thing I have tried so far. I really have not had a need for these slower burning powders and as such i have not kept much on hand. I have RL22 for my 7RM but only about a half a lb. left. this component shortage was the worst time to start a wildcat I think.

With 64.0gr of H1000 there is still a fair amount of room in the case. I filled a case up to the base of the neck and then dumped the powder in the scale pan and got 72.5gr so i am hoping that I can go beyond 64.0 and make it up closer to 70.0 grains. Gonna keep moving up slowly and carefully and see how far I can go. I was thinking about going to RL25 or RETUMBO if I needed to, but so far I am still on the lighter side of things with the H1000 so I still have a good amount of hope for it.

[yobuck]

ive been playing with my 6.5 short mag for several years now. i have a little more than 300 rounds
down range at this point. i love the cartridge but wouldnt have used a 243 to start with again.
id have bought a short mag and rebarreled. the magazine/ feed was a nightmare and i wanted a magazine.
i know you have a 6mm but some of my information might prove usefull.
i have pretty much settled on 63 gr h1000 w/a fed 215 and a berger 140. 80 clicks puts me on a rock at 1050.
the 140 smks shoot as well @100 but dosent carry the distance quite as well although close.
and no dead deer dont question any of that.
both rl 19 and rl 22 will give the velocity also. 7828 is close also. but the h1000 seems friendlier with pressure
in my gun. also i found norma brass to be better in that area than win brass. ive already replaced a bolt face
while testing with win brass and the reloader and 7828 powders. im using 270 wsm brass necked down. 1 step
thru a f/l lee die i bought on ebay. the chronys tell you something different each day. sometimes alot different.
actual shooting results is the best in my opinion for velocity information. based on that it appears im in the 3350/3400
area with the 140 in my gun. ive not tested lighter bullets at distances beyond 100 yds. im tempted to try 130 bergers
but that would be about the lightest id consider. im not sure at this point if id shoot at a deer much beyond about 800
with this gun. it would depend alot on conditions. i have larger cartridges that will walk the same talk for that purpose.

[bootsmcguire]

Well I did it, I made it past 3650 and even up to 3740. However 3740 is obviously over preassure.

6mm-WSM
105 A-Max over H1000 lit off with a Rem 9 1/2M seated out to the lands.

65.0gr = 3435
66.0gr = 3432
67.0gr = 3562
68.0gr = 3572
69.0gr = 3651
70.0gr = 3702
71.0gr = 3744 compressed load
72.0gr = ----
73.0gr = ----
Tested at 60*F with Chrony 12ft. in front of muzzle.

Only the 71.0gr charge gave me a slightly heavy bolt lift, but it blew a hole in the primer right where the firing pin struck, exposing the anvil. None of the primers were backed out of the case at all, and the 70.0gr showed the slightest bit of flattening, and the 71.0 was flattened. Not the worst flattened primer I've seen but flatter just the same. Due to these signs I chose not to fire the 72 or 73 grain charges.

I think I am going to load up some more of the 69.0gr loads and try to make some groups and see how that does. I am currently calling the 70.0 a very max charge, so if the 69.0 give decent groupings then I'll start playing with seating depth, etc.

Once I can locate some, I may do a work up with possibly RETUMBO or maybe RL25 depending on what I can find, but leaning towards RETUMBO at this point. Might try that just to see if there is a bit more to be had from this round with a bit slower powder.

[scope eye]

I don't think you will see any gain with Retumbo, you probably will with they RL25, in any case those sure are impressive numbers,
how hot did the barrel get, and how hot was it when you were launching the 70s and 71s. nice work

Dean

[bootsmcguire]

Air temp was 60 degrees, the barrel itself never even got hot to speak of. I could touch it all the way down even near the chamber area and only tell that it was just warmer than the rear action. My 22-250AI gets hotter after 5 shots that this barrel did and the 250 is a heavier contour. Brass wasn't hot either. Pulled it right out after firing for inspection and wasn't even very warm to speak of.

Maybe your right about RL25. I am more familiar with the RL series powers, but I have seen RETUMBO on the shelves last trip for powder so availability was my motivation there. The H1000 is giving satisfactory speeds, hopefully they will make good groups. The 61.0gr charge that I shot for groups and posted about earlier in this thread tells me the barrel will shoot accuratly. I did fire off 8 shots in a row of the 61.0gr charge today that I had already loaded, and a dime will easily cover the group, if you exclude 1 flier that I jerked.

[snowgetter1]

Great work and good numbers. And such a tempting idea.

[bootsmcguire]

A couple people have asked where I got my barrel so I figured I would share here. The blank came from Green Mountain Barrels. It was a CM 1-9" twist.

I sent the blank to www.apachegunworks.com for Jim to do the chambering, threading, contouring, and bluing. It came back to me top notch. Beautiful machine work ( I am a machinist so I can appreciate such things) and a nice matte blue finish, it all turned out great and I am going to be doing business with Jim again.

[Hotolds442]

Putting this one on my radar....

[bootsmcguire]

I really need to get back out and do some more work with this. The extra cold winter this year + 3 kids + fall and winter hunting seasons not to mention a couple of other barrels with new to me chamberings kind of forced the 6WSM development into a low gear.

I can say that the 69gr charge of H1000 was giving decent groupings in the .6" range on down to the .3" range, but its a bit abusive to the brass with 3-4 firings making the primer pockets loose enough to the new primer to nearly fall out.

I did a little testing with RL25 a while back, and I don't have the data here right now, but I was able to get a couple of grains more before seeing signs of pressure. I didn't have my Chrony (I can't find the head unit for some reason). I picked up some US869 to try if need be, but I think I would rather try H50BMG since it is an extruded and has the same burn rate as the US869, but gotta get what you can and do the best with it.

I may end up sticking with the 61.0gr of H1000 load for a bit, cuz a 105 doing 3300fps is still nothing to sneeze at.