Have you had this type of problem, or is it a problem at all?

I am following the data of the Hodgdon reloading Manual for a .338 Magnum 250-grain bullet with IMR 4350 powder, but it seems that the velocities I am getting exceed the velocities shown in the manual.

According to the data, a maximum of 70 grains of IMR 4350 should produce 2,707 fps. However I get the following at the range (Chronograph 16' ahead of the muzzle):

a. 250-grain NOS Partition
69 grains of IMR 4350
Average speed from 3 shots = 2,704 fps.

b. The same bullet
70 grains of IMR 4350 (maximum listed)
Average speed, 3-shots = 2,716 fps

The rifle is a Ruger stainless, M77 MK II, with a 24" barrel. I have shot at least 600 rounds from this rifle. The bullets I used last year were Moly coated, but I have already cleaned the bore with JB compound. This rifle's bore is very slick and clean.

I can's see any signs of excessive pressure, and the bolt extracts the fired cases with ease. I weight the powder for each case with an electronic scale, and I am extremely careful with it. The most accurate loads are the ones at maximum (70 grains).

I have had a chronograph for years, but I have never used it until now. Should I be concerned about the extra speed and come down to 69 grains, or is it normal?

[This message has been edited by Ray, Alaska (edited 05-07-2001).]

Ray,

Loads listed for H4350 are for an Australian powder called ADI 2209, which Hodgdon sell as well as other Australian powders.

The burning rate is similar to IMR 4831 and in some batches a little bit slower.

So effectively you have increased Hodgdon's loads.

But Hodgdon's loads will be "lawyer" loads so they won't be too much in the first place.

Mike

[This message has been edited by Mike375 (edited 05-07-2001).]

Mike: I should have left the chronograph in the closet! I usually follow reloading data and don't worry about using a chronograph. Now that I have used one I am starting to be uncertain about my methods of reloading.

Ray,

As long as your loads do not show any sign of high pressure, there is no reason not to use them.

We do quite a lot of reloading, and on many occasions, some rifles will reach their limits pressure wise long before getting to what the books show as maximum loads.

On other occasions, we can exceed the book loads by several grains, and still show no sign of excessive pressure.

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saeed@ emirates.net.ae

www.accuratereloading.com

Ray,

You should be very aware that loading data for H4350 should not be used for IMR 4350 (or for that matter for XMR4350). They are all different (but similar) powders.

Having said that, if you are experiencing no problems, then you have no problems!

Velocity from the same load can easily vary 100fps or more between rifles.

Don

Ray keep using the chronograph that is the only way you really know what the rifle is doing each rifle is differant. If you own more then one reloading book you well soon find out that none of them are the same. I have books from the forty's till now they are all differant. I would say that if are getting a lot higher velocity then 3 or 4 books show I would back off a bit. A 100 fps isnn't going to make a dif. to any thing you shoot.

One other consideration is the chronograph. Many are affected by light conditions and the velocities indicated will be nothing like those in manuals.

With IMR4350 you could easily attain velocities exceeding those you list without any problems. In fact, with some of the slower powders like H4350, H4831 and RL22 you can reach 2800fps, and more, without external pressure signs. Bob

Thank you for all the responses.

Using the chronograph was a very nice experience. I was a little apprehensive at the beginning thinking about the chance of shooting through the screen, but once I set my rifle scope at its lowest magnification I could clearly see the chronograph. Then when I realized the velocities seemed to be higher than the ones shown on the manual, I worried a little. I will continue using the chronograph, because I can see that its use opens the door to new things in reloading, and will help me gather data for a ballistics program I use. Hmmm...Reloading is turning into fun!

I noticed that on a group of three shots, the first shot would be the fastest, then the speed would drop for the other two. For example, 2,734 fps for the first shot, 2,711 fps for the second, and 2,703 fps for the third shot. This was the fastest 3-shot group of the test, and later the most accurate on paper at 100 yards.

I have been using 230-grain FS bullets for the last few years, and have killed several moose with it. The FS is not the most accurate bullet from my rifle at 100 yards, but past 100 these bullets print pretty close to each other on moose. But I have heard so many good comments about the .338 250-grain NOS Partition that I have decided to give it a try this year.

I use RL-19 or RL-22 with the 230-grain FS bullet, and used IMR 4350 with the 250-grain NOS Partition.

Hi, Ray:
The first thing any new chronograph user should do is round up at least 3 .22 rifles and chrono them with the same box of shells at the same time. You'll see that some barrels are faster than others. Now try several different .22 loads and select the most consistent.

No chrono can be consistent unless lighting, temperature and alignment is constant. That means an indoor range. So if you chrono outside, shoot at least 5 shots of your favourite .22 ammo over the chrono before you start popping off Noslers. You'll know if you've got a bad setup rather than a bad load. One Nosler costs as much as half a box of .22s.

Test a new brick of .22 against your old brick when it runs low. My current lot is 50 fps faster than my previous test lot.

Your load is 1/2% faster than Hodgdon's and that is a very minor difference, as the other guys have pointed out.

Your chrono is a very useful tool, but you have to learn how to interpret what it's telling you.

Bye
Jack

Ray: I cannot see that you hae a problem at all. So long as that load produces no high pressure problems in your gun us it.

I have personally used the same load of 70 grains of IMR 4350 behind 250 grain bullets in two different .338 WIn Mag rifles for many years now and have never had any problem of any sort.

And when using the 250 grain Sierra boat tail bullet, I routinely get about 75 feet per second faster than the Sierra manual suggests I should get. I am not complaining, trust me.

I have used 70 grains of IMR 4350 or 72 grains of RL 19 in these two rifles with Sierra, Nosler, and Speer bullets of 250 grains and have never had a problem.

Keep shooting that load and forget the fact that you are getting a little faster than the book says. Each gun will be different.
My buddy and I both just tried N133 powder in our Remington 700 rifles chambered in .223 Remington. With the same loads, his rifle averages 180 fps faster than mine! Go figure.

R F

Ray,

Things sure sound ok to me. The one thing I will caution you though, is that is data is worked up for a conventional cup core bullet, and you swap to a partition type bullet, don't be suprised if you gain 50-100 fps for the same load, and resulting higher pressures. In my 35 whelen ackley, going from a 250 hornady to a 250 a-frame increases the velocity 70 fps for RL15 and 100 fps for VV N550.

By all means use a chrono, it is the least exspensive and best means of correlating what your loads are doing in relation to the factory data. If you are getting higher velocity then the books, then you are doing it at higher pressures. I really can't imagine working up loads w/o a chrono.

Ray,
When starting to chronograph your loads make sur you load one extra to shoot before you start chronographing. The first shot being fast could be from cleaning your barrel and haveing some oils left in the bore. By fouling the barrel you will eliminate this. I had a 416 Rigby that after cleaning and running patches down it until it seemed nothing else was present would always shoot the first bullet 5 inches higher than the sited in group. 470 Mbogo

Ray Alaska. According to the manual, you should get 2707 FPS with 70.0 gr. IMR-4350. 69.0 gr. gives you 2704 FPS, and 70.0 gives you 2716 FPS, right? Something ain't right here. The fact that there are no apparent pressure signs is not the issue. The velocity gain you got between 69.0 and 70.0 gr. was only 12 FPS. It should have been more. This leads me to believe you've passed a pressure plateau that is borderline, too much.
Pressure will rise on a linear basis until a certain point when velocity no longer rises in relationship to powder charge increase.
Hypothetical example. Say you start with 66.0 gr. for say 2450 FPS. 67.0 gives 2500 FPS. 68.0 gives 2550 FPS 69.0 gives 2600 FPS 70.0 give 2610 FPS. OOPS! You've reached a point where you are actually past the max load for your rifle. Under the circumstances shown in the example, dropping back to say, 68.5 gr. might be the prudent way to go. Any animal shot woth a .338 Mag. darn well won't notice the slight loss in velocity, and you won't be picking pieces of the bolt out of your teeth.
That's one of the beauties of a chronograph. Kind of like an early warning system. I do seriously think your load is slightly over max for your rifle. Check it out, please.
Paul B.

Thanks, Paul B.

I will give your idea a try. It only makes sense that I doublecheck before I make my handloads with this powder/bullet final.

[This message has been edited by Ray, Alaska (edited 05-11-2001).]

Paul B,
As a matter of fact once you reach the saturation point, so to speak, or a full max load, there is a point of no return reached and very little is gained by increasing the load a grain or two as you may well gain only a few FPS, but if you increase it two more you may be beating the hell out of the bolt trying to get the case out or worse you may not have to beat it out, it may be in your face...so He is at a good max load and should in fact cut it one grain as 16 FPS is nothing and his cases will last longer..

Tweeking velocity is bunk, bunk, bunk...

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Paul,
Then thats what you said isn't it!! Sorry, happens when you peak age wise also!! (grin)

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Hi, Ray:
A couple of things to consider. How does Hodgdon's load of 70 grains compare with other people's manuals? Nosler #3 shows 68 grains as max. Hornady # 4 shows 67 as max. Speer #11 shows 69 as max. Sierra #4 shows 70.2 as max. Lyman #47 shows 72 as max. So you're definitely getting there.

As Paul B and Ray say, you may have hit the wall, but you might be looking at a statistical bip too. I can do the stats if you post the velocities for all your shots at 69 and 70 grains. Standard deviations and t-tests are useful if enough shots are fired. I'd want at least 10 with each powder weight. A 3 shot average isn't worth much and a 3 shot standard deviation is worthless.

I like Ed Harris' test for max loads. IIRC, if the primer pocket is tight after 10 reloads, you're OK. If it isn't, reduce 5%. If it's loose after 5 shots, reduce 10%.

You may have room to move, but proceed with exterme caution.

If anyone is a professional statistician, please jump in.

Bye
Jack

Jack: I comparing reloading data from different manuals today, and I noticed how much they differ from each other. You are correct when you say that standard deviation from three shots is not enough.

I fired a few more rounds at the range today, and also noticed that the chronograph was giving higher readings than before, but it was warmer today than the last time I was at the range.

Overall, six to eight shots from my rifle produce average velocities that are a little higher than those shown on the Hodgdon manual, somewhere from 16 to 40 fps so far. I started at 68.5 grains of powder, and stopped at 69.5 grains. The difference between groups was around 40 fps (from one to the next higher one). Again, from 69 to 69.5 grains of IMR 4350 accuracy at 100 yards was quite good, while it deteriorated a little below 68 grains.

Thanks to all of you for all the responses. All I can say is that I have learned quite a lot from your ideas. I copied all of the information and saved it on my hard drive for future use.

My 16-year old shot my .338 two times today, and his response was "Dad, it didn't kick too much, maybe a little more than my .30-06." (I had a KDF muzzle brake installed, of course).

Hi, Ray:
Looks like you've found a sweet spot at 69 grains. Glad to be of help.

Bye
Jack