exceeded max velocity with starting charge?

[HARV6]

Just loaded up and shot my first 10 40s&w rounds. Everything seemed normal except the velocity. This was supposed to be a starting charge, but my chronograph says the velocity was over what you'd see with a max charge. I definitely won't increase the charge, but should I back off of my starting load? I'm using 180gr Frontier CMJ bullets and their website says to use FMJ load data. My Lee manual listed 6.4gr of Unique as max, velocity 1065. I read somewhere that these bullets were electropated like Speer GDHP. Alliant lists a charge of 6.7 grains of Unique with the 180 GDHP, velocity 1000fps. What I loaded was 6.0 gr and velocity averaged 1085. Highest was 1125. Primer was cci 500.

 

[CMV]

Did you shoot some factory or some other known load over your chrony first to make sure it was reading properly?

Mine has told me .45ACP is going 250 FPS and it has also told me it was going 1800 FPS. I don't think think either would be possible from a 1911.

Anyway, it doesn't take a lot of fluorescent lighting near my Chrony F1 to make it go haywire. Sun at a steep angle will throw it off too. Or sun poking in & out of clouds. Might just be my particular one, but it's fussy so I shoot something known first to make sure the reading is what i would expect.

 

[JDGray]

How far back from the chrono were you?

 

[HARV6]

Yeah I've shot factory stuff over it before and it was averaging pretty close to box velocity. I have seen what scattered clouds and shadows do to my chrony but I'm pretty sure I had ideal conditions for it today. These 40's were shot at 130pm completely overcast in an open field. Every one of them registered.

 

[HARV6]

I'd say 10-12ft back off the chrony. but I haven't shot this particular pistol over a chrony before.

 

[gamestalker]

Some of the variables created in the books comes from the test barrels or firearms used, primers used, and bullet types are as well a factor. One must also consider that some barrels are faster/slower. For instance one firearm may stay locked up longer. This would certainly effect velocity because the pressure curve may be higher, longer, or both. OAL and brass length will also effect velocity.

 

[hogrdr]

what do the primers look like, flat or not, cratered?

 

[Lost Sheep]

Higher readings? Simple alternate explanation.

If you are using a Chrony brand chronograph, did you ensure the thing was open all the way. If the body of the instrument is not opened the full 180 degrees, you will get higher readings than true. Higher up, even faster. Lower down (closer to the sensors) somewhat less of a boost in readings.

Lost Sheep

 

[MEHavey]

First, look at this image:

The Frontier is electro-plated, not jacketed. What you are shooting is effectively a lead bullet as far as bullet upset/bore sealing goes. As a result, you actually get somewhat higher pressures (and velocities) for the same powder/bullet weights as compared against true jacketed bullets.

If you accept that, and refer to any manual for cast lead (aka Lyman's 48/49th and/or Cast 4th ed), consider yourself slightly over max, and back off to an even 1,000-1,025 fps, which would likely be at/just under 6.0gr of Unique

 

[brickeyee]

Yeah I've shot factory stuff over it before and it was averaging pretty close to box velocity.

"Before" does not count.

You should always fire some factory ammo over the chrony every time you set it up to make sure everything is operating correctly, every time.

 

[HARV6]

wow

Just looked at the primers really close for the first time. Looks pretty warm to me. Especially the lone federal shell.

 

[rsrocket1]

CCI primers are very hard so reading them is pretty tough. I load my 180g 40's with 5.0g Unique for mid 900's fps and up to 5.6g for top end of the 900's.

Running a QL sim of 6.0g Unique under a 180g Speer GDHP @ 1.135" would get you 1097 fps out of a 4.25" barrel gun and 35,000 psi pressure which is right at the SAAMI max. That's safe for the gun, but any variation (charge, seat depth, temperature) puts you over the max which probably won't blow up the gun, but really isn't needed because it just wears it out quicker and batters your hands more.

I can tell you that 5.0g Unique is certainly not below the minimum and works the action just fine on a S&W M&P so don't be afraid to back off of those 6.0g charges.

 

[popper]

You started 10% back from MAX, I usually go 10% back from mid(you can do that with Unique). 5.5 is my load for 180 plated or CB, 6 is max.

 

[NCsmitty]

I don't know what other variables that you have at work here, but you are cratering primers, and that shows me that your load is too hot in that pistol.
Double check your scale and measure, and if your charge drops are accurate, it's time to back off the charge a bit.


NCsmitty

 

[HARV6]

The only other variables I can pin down are OAL of 1.130 and a light crimp on the Lee Factory Crimp Die. I'm thinking I will dial back the powder to 5.5. When I do get a chance to load/shoot again i'll test some factory ammo out to get a baseline.

 

[Hogpauls]

Harv, the Alliant website of 6.7 grns is max with OAL of 1.12. Speer lists a starting charge of 6.0 grns. and 6.7 as max, both with 1.12 OAL.

 

[LightningMan]

I was shooting Rainier plated 180 gr bullets with 5.5 grains of Unique, a OAL of 1.125 today, and thought they had plenty of snap to them. Can't imagine what 6.0 grs would be like. LM

 

[HARV6]

I've only shot blazer brass 180 and 160, and Federal HST 180's. And had them alternating in the mag to see if I could tell the differ ence. I couldn't. The reloads mentioned above didn't seem to recoil any different. I am shooting them out of a Ruger SR40 though, which are reported to transmit recoil less than any other 40s&w.

 

[showmebob]

I just posted on this very same problem! I got all the usual answers but none of them applied to my situation. Our notes would compare very closely.

I've matched componets with the Speer manual and still had the same results. I've called the powder manufacturer and Speer with nothing coming from it. I've tried 4 different test with the same results.

Now the interesting thing is if you load with Titegroup your chrono results will match the Speer manual exactly.

So, I hate to say it and know full well what the results will be, but, dare I say could the manual be wrong? Or, is this just something that no one can explain?

Speer used a real gun with a 4 inch barrel (just like I did). I used the same primer, bullet, powder, and Federal cases. Same COL. As I said using T.G. the speeds were the same. Unique, speeds were way high as was the recoil. I started with 6.0, went to 6.4 and pulled the bullets from the 6.7 loads.

I've decided to use 5.7-5.8 of Unique as the MAX load. 5.7 runs 970fps and that's good for me regardless of what the manual says.

Good luck and let me know if you find an answer to this problem that makes sense. I'd really like to know!

 

[ArchAngelCD]

It's my opinion your charge weight is too high because the bullets you are using are more like lead bullets than jacketed bullets. You use less powder with lead bullets than jacketed as we all know.

My Lyman 4th Edition Cast Handbook lists a 180gr FN bullet with Unique and the charge weights are 4.6gr to 5.2gr with a velocity of 998 fps and an OAL of 1.130". A Max charge of 5.2gr is a far cry from the 6.0gr charge you used and a whole lot different than 6.7 grains. Now we know the charge weight of a plated bullet can be slightly heavier than straight lead but not not almost 23% more!!! You charge of 6.0gr is 13.3% higher than Lymans Max listed charge for a 180gr lead FN bullet.

I would try dropping back to 5.0gr and see what the chrono tells you and then increase to 5.2gr if needed but not much more. (IMO of course)

 

[MEHavey]

...could the manual be wrong? Or, is this just something that no one can explain?

Neither.
The manuals are right, and the explanation is fairly straightforward.

You are shooting the structural equivalent of cast/lead bullets, not jacketed.
Go the cast loads as suggested by Posts #9 and #20 above and you will be fine.

 

[longdayjake]

The Frontier is electro-plated, not jacketed. What you are shooting is effectively a lead bullet as far as bullet upset/bore sealing goes.

You are shooting the structural equivalent of cast/lead bullets, not jacketed.
Go the cast loads as suggested by Posts #9 and #20 above and you will be fine.

This is not true. Depending on the brand of plated bullet used, the plating could be thick enough to act more like a jacketed bullet. My experience has been that plated bullets act more like jacketed bullets than they do like lead cast bullets. No plated company that I know of is still telling their customers to use cast data for their bullets. If the bullets are Powerbond or X-treme, I would recommend using full jacketed data as they have the thickest plating aside from Speer TMJs. Frontier bullets claim to be thickly plated and they also claim to be shootable at high velocities. This suggests that regular jacketed data is probably fine.

If my experience has shown me anything, you will have more trouble with these bullets if you use lead cast data than if you use jacketed data.

My guess is that you have found a particular powder and bullet combination that your gun seems to shoot faster than the test barrels. I don't chrono my pistol loads but I have found loads in most of my rifles that differ from what the manuals predict.

 

[showmebob]

HARV6
Since we both are having the same problem. What is the lot number on your Unique?
Do you suppose there was a "off" batch and we both have the same lot?

 

[showmebob]

MEHavey
[Neither. The manuals are right, and the explanation is fairly straightforward.
You are shooting the structural equivalent of cast/lead bullets, not jacketed.
Go the cast loads as suggested by Posts #9 and #20 above and you will be fine.]

Please review my post below.

[Speer used a real gun with a 4 inch barrel (just like I did). I used the same primer, bullet, powder, and Federal cases. Same COL. As I said using T.G. the speeds were the same. Unique, speeds were way high as was the recoil. I started with 6.0, went to 6.4 and pulled the bullets from the 6.7 loads.]

As you will see I used the same componets as stated in the Speer manual except for the Speer cases. So, using the componets listed in their manual the speeds should be close regardless of plated, lead, thich plated, fmj.
In my case I used both Precission Delta FMJ bullets and Speer GDHP.
The test came out just fine with Titegroup but way off with Unique. And yes I'm sure the charge weight is correct.
I appreciate everyones feedback to the OP and to my earlier post.

At this point I see only 3 possibilities: 1, the chrono just doesn't like Unique even from 12 feet away. 2, The OP and I both got a "off" batch of Unique. 3, The speeds listed in the
Speer manual are incorrect.

Please chime in if there are any others, I'm all ears...............or eyes as the case may be!

 

[MEHavey]

Frontier bullets claim to be thickly plated and they also claim to be shootable at high velocities.
This suggests that regular jacketed data is probably fine.

I'm going to go grab some of the above and test w/ both TG and Unique. It's going to
have to be w/ 38SP (in a 357 gun) to get compact case size married to higher pressures,
but I'll check against predictions from both the Manuals and QuickLoad using an Oehler.

To be honest, I don't particularly like either 9mm or 40 S&W as far as reload
predictability goes until baselined over a chronograph. I find them both, quite
frankly, ...squirrelly


(post script: I have always made it a practice to treat plated bullets as lead until the
chrono tells me different. They take as much as 10% less powder to hit the
same pressures/velocities as jacketed. In fact you can overpressure things in a
hurry w/ lead. As far as shooting high velocities, goes, however, you (and me both)
can push lead very hard -- I'm running 1700++ w/ a 255gr plain-base Keith
45 Colt rifle -- as long as the bullet is properly sized/upsets in the bore and seals
against the sides.)