When is a compressed load dangerous?

[Dr Killdeer]

I need the benefit of experience for this one! How much can you compress a stick powder?

I’m attempting to work up a load for my 30.06 using a 180 grain Nosler Accu Bond ahead of 57 grains of H-4350. I’m using CCI large rifle primers and Remington brass, since I have a ton of it.

For this bullet the Nosler manual says the most accurate load tested was 57.5 grains of H-4350, which is also the maximum load. I decided to try 57.0 grains. The book C.O.L. (3.300) is way too long for my rifle. I’m seating to a depth of 3.285, which puts the bullet about 15 thousandths off the lands, but 57 grains of H-4350 fills the case to a smidgeon below the neck.

This is unfamiliar turf! The bullet is really compressing the powder and I’m beginning to have second thoughts. That’s why I haven’t actually tested the load yet. How much compression is too much? What are the dangers involved, if any?

I could reduce the charge and/or go to a different powder, but this question will still haunt me. Any help will be greatly appreciated.

[.284]

I don't think I can give you a definitive answer to your question. However, I have seen published load data showing 103% load density as a max....cannot remember the exact load. The point is there are loads out there that allow the reloader to pack in the powder. As for your situation, I would keep your loads and work up to them. Load some at the starting load data and look for pressure signs. This is a proven method to insure safety.

[briandg]

You are talking 0.015 difference in OAL, right? insignificant.

Is your 0.015" of free bore enough? not in my opinion.

Does crushing that powder charge represent a danger? I doubt it, as powders like that and 4831 function even when compressed, you have to worry about total charge weight more than you do total volume.

Are you worrying too much about this? Yes. You are assuming that the load that they tested as being most accurate will also be more accurate in your rifle, and that is probably not going to be the case. Stay away from the max load, IMO.

Lastly, are you serious that you are going to start your experimentation at 1/2 grain under the max load? Really? DON'T DO THAT! That is a maximum, not a starting load, and not a normal load. Just because it has been published doesn't mean that it is safe. Maximum loads can cause firearms to fail. Reduce that thing some more to start.

[brickeyee]

For this bullet the Nosler manual says the most accurate load tested was 57.5 grains of H-4350, which is also the maximum load. I decided to try 57.0 grains.

Sounds like a good way to blow something up.

Start 10% under or at the starting load if one is specified.

That would be about 51.8 grains and work up from there.

Do you have a reloading manual?

Did you READ the manual?

40,000+ PSI is not to be screwed around with.

[Dannyl]

Killdeer,
My HORNADY manual lists 55.3 Gr as a max load for this weight of bullet, with a COL of 3.240
I also load for 30-06 (180 Gr' SST and Interlocks)

Seeing that they are not much different in dimension, I find it hard to believe that NOSLER would recommend a load that is nearly two grains higher/

my COL is longer, I use 3.366" and even then if I load 56.3 Gr of S365 I get just under 2700 FPS. (S365 local powder, nearly perfect match in burning rate to the IMR4350) this is certainly a warm load that flattens primers noticeably and I'd think twice before going further up with weights.

I am not going to ask you why you want such velocities with a heavy bullet, not my concern. but I would urge you and anyone else reading this thread to re-consider.

I am also curious and have to ask how did you reach the decission to use this particular charge? under normal load development with whatever technique you use, one starts at the lower or medium loads and works his way up in small increments (in 30-06 usually 0.3 Gr for starters) and watches for signs of excessive pressure.

Brgds,

Danny

[Slamfire]

Heck, I don’t know.

If you were compressing something like bullseye, well your 30-06 is going to go boom. We all know that, fast burning powder really causes problems in overcharges.

But you are asking about a slow burning powder.

If the weight of that slow burning powder is enough to be overpressure, then you are going to have an overpressure load.
If you don’t have enough slow burning powder in the case to be overpressure, than compressing it is not going to cause an overpressure load.
I am assuming that the majority of propellant grains are not smashed into tiny bits. That might have an effect on burn rate.

I know this is not a 30-06, this is a 308. I have lots of IMR 4350 and I mostly shoot gas guns and 308. So I tried to see how fast I could push a 155 Nosler with IMR 4350. In commercial cases 46.5 grains is just below the case neck, with military just at. Forty seven grains is a heaping load in a military case. Seating a bullet to depth requires crushing the powder column the length of the case neck.

I did not notice any overpressure problems with 155’s.

Years ago, I tried 190’s and 47 grains IMR 4350. On a hot day I had pierced primers. I think it was due to too much powder not the crushing that took place. I can recall seating a 190 and then watching as the powder pushed the bullet back.



Pre-64 M70
24 " Krieger Barrel 1:10 twist

155 Nosler 46.0 grs IMR 4350 wtd, Lot 6164 (60's) mixed cases CCI 200 OAL 2.780"

29 May 2010 T = 82 °F

Ave Vel = 2418
Std Dev = 17
ES = 60
High = 2441
Low = 2381
N = 10

155 Nosler 47.0 grs IMR 4350 wtd, Lot 6164 (60's) mixed cases CCI 200 OAL 2.790"

29 May 2010 T = 82 °F

Ave Vel = 2490
Std Dev = 17
ES = 59
High = 2515
Low = 2456
N = 10
best IMR 4350 group

[SL1]

DrKilldeer,

I think you have the wrong data or you mis-posted your load specs.

I have 2 Nosler manuals (#s 2 and 6) and neither lists H-4350 with a 180 grain bullet. They do list IMR-4350, but that is a DIFFERENT powder, and they don't list anything like 57.5 grains as the max load for it, either.

Where they DO list H-4350 is for their 165 grain bullets, and that does show a max load of 57.5 grains. SO, YOUR POSTED INFO SEEMS TO INDICATE THAT YOU ARE USING DATA FOR THE WRONG BULLET! Your 57.0 grain charge looks like about a 2 grain overload for your 180 grain bullet!

Also, the Nosler data was worked-up in Nosler cases. Are YOU using Nosler cases? If not, then your might have less capacity and that MIGHT be the reason that 57 grains is filling it "to a smidgeon below the neck." But, with the 165 grain bullet instead of the 180 grains, is that really substantially compressed? The Nosler manual says that it is a 101% fill with the 165 grain bullet, so that seems reasonable.

And, I don't see where the manual lists the COL for their pressure-tested cartridges. All they list is the SAAMI max at 3.340". So, where did you get the 3.300" you attributed to their manual? Also, it seems a strange coincidence that you hit your rifling at 3.300" [= your 3.285" COL + 0.015" jump]. Did you mis-post on that?

SL1

[briandg]

You know, this is one of the things I really hate about discussing reloading online. I hadn't even caught that it was hodgdon. Not that it makes a lot of difference, either one, hodgdon or IMR, there were fatal flaws in that information, but with the stakes as high as they are, I never look online for community based information.

[Doodlebugger45]

I agree that it seems the OP mixed up the wrong powder/bullet info. On Loaddata.com, I searched all the different loading manuals for ALL 180 gr bullets using H-4350. I even searched using IMR 4350. They are different powders, but extremely close, and their start and max charges are typically within 0.2 gr of each other. In any case though I could not find a single manual that recommended even 57.0 gr of either 4350 powder for ANY bullet in the 180 gr range. About the highest charge weight for those powders that I saw as a max was around 55.5 gr. If it was me I would drop down to around 51 gr and start from there.

[steve4102]

Start 10% under or at the starting load if one is specified.

No reason to do this. "Starting" load is just that, The place to "Start" going below start is not necessary and with some powders dangerous.

[oneoldsap]

Nosler #3 lists 55.0 Gr. IMR-4350 as a max charge , filling the case to 102% capacity . with a M.V.of 2760 FPS . With the selection of powders that are available why mess with compressed loads at all .

[SL1]

Steve4012,

I think the advice you quoted

Start 10% under or at the starting load if one is specified.

was intended to say "Start 10% below max if no start load is specified (as in Alliant data) or at the start load when one is specified." Sound advice.

Your intended advice to not reduce "start" loads is also wise, since there can be some safety problems with doing that with the wrong powders.

However, "start" loads are not really the same as "minimum" loads. Start loads are intended ONLY to be assured of low-enough pressure to avoid overpressure when a lot of factors go the wrong way all at once. The idea is to not start higher, but to work-up from there toward maximum as you lookf or the best load for your gun.

True minimum loads may or may not be lower than the start loads. True minimum loads are determined by several factors, including the potential for "secondary explosion effect", the potential for unstable burning, and the potential for lodging bullets in barrels of revolvers. When going for reduced loads, you actually work-DOWN and do not go below minimum. Few manuals actually provide minimum loads. But, some vendors web sites do discuss minimum safe loads for powders that are often used for reduced loads because they are known for stable burning over a very wide pressure range.

SL1

[Jim243]

I am glad you are having second thoughts. I had second, third and forth thoughts about replying to your post.

1st problem is your rifle. Your chamber and throat should be 3.340. If 3.300 is not fitting into your rifle, you have not bumped the sholder on the case enough to put it in spec. Or you are using a 270 case for 30-06, check the head stamp.

2nd problem is your bullet, OK I found where you got your load from (Hodgdon's 2010 Annual Manual). But that load and OAL is for a Sierra 180 gr SPBT, not for a Nosler Partition. Different bullets, different shapes, different configurations. The bullet and powder mfgs go to a lot of expense and trouble to give you loads for their products USE IT NOT SOMETHING ELSE.

The 3rd problem is the amount of powder you want to use (by the way 57.5 of H4350 is not a compressed load, it is a MAX load). I have a friend that got me into reloading, and I swear that he hates his guns because every bullet put into a case has to have the absolute max amount of powder and then some. All that will do is stress your firearm and burn out your barrel. I don't give a rats A-- if the bullet will get there 1/1000 of a second faster or not, the animal will be just as dead. But I don't want to have to go out and replace my firearms that often. Just start with 55 grains and work your way up to the point your gun is getting 1 MOA groups.

If I seem a bit harsh, you are correct, it is dangerous enough just to make correct ammunition, but once you start changing the formuals it really gets hairy. Be safe and double check everything, no tripple check.

Jim

[Gunplummer]

Something else you should watch(With compressed loads) is if you do not crimp your bullets, the bullet will creep out of the case. Then when you load one in the chamber, it will be jammed right into the rifling. I usually do not crimp my loads, so I don't know if crimping stops this or not.

[Dr Killdeer]

This goes beyond having egg on my face!

Admittedly, I misread the Nosler specs. The 57.5 grains of H-4350 is a max load for the 165 grain bullet. When I also checked Hodgdon’s data and I saw the 180 grain Sierra at 57.5 grains, I further mislead myself into complacency.

I can’t believe I made a Dick and Jane mistake. I looked at the Nosler data several times and instead of seeing a165 grain bullet, I saw 180 a grain bullet. How can that happen? Always in a hurry! But this incident has shaken my confidence, which will serve as a lesson in humility. Now, I need to disassemble those loads and start all over again.

One thing is certain! If that bolt lets go because of an overcharged load, there’s a good chance my head could go with it. (At this point I feel like it would be an improvement.)

No remarks are too harsh when it comes to reloading. Thanks to the people on this forum who are willing to share their experience, I got lucky before I squeezed the trigger.

Joe

[.284]

Not trying to be condescending at all but, let's take a moment and look past the "egg on your face".

I think the most important thing to learn here is that safety is paramount. Working up from a starting load insures two things. First, it allows you to look for pressure signs. Second, just because some load tested in a gun (that is not yours) was the most accurate means nothing to you. Your gun might shoot the best groups with the most consistent velocities using the starting load. One of the reasons most of us handloaders do what we do is that we love to shoot. I see nothing wrong with trying a bunch of powders and bullets. However, a max load with one powder type might be as safe as sitting in your favorite easy chair where another powder might be the cause of a bad day.

You did the right thing by asking the question before you pulled the trigger. Good luck with your 06

Jeff

[azar92]

Killdeer,

For what its worth QuickLOAD predicts in the .30-06 using the 180g Nosler AccuBond with H4350 that 55.0g is the maximum charge. The predicted pressure for 57.0g was 66,658 PSI and at 67.5g 57.5g was 68,577 PSI.

Cartridge          : .30-06 Spring.  (SAAMI)
Bullet             : .308, 180, Nosler AccuBond 54825
Useable Case Capaci: 57.562 grain H2O = 3.737 cm³
Cartridge O.A.L. L6: 3.285 inch = 83.44 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Hodgdon H4350

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-10.0   95    49.50   2471    2440   42827   7979     93.7    1.356
-09.0   96    50.05   2497    2493   44228   8074     94.2    1.337
-08.0   97    50.60   2524    2547   45677   8166     94.6    1.317
-07.0   99    51.15   2551    2601   47178   8256     95.0    1.298
-06.0  100    51.70   2578    2656   48731   8344     95.5    1.280
-05.0  101    52.25   2604    2711   50333   8429     95.9    1.261
-04.0  102    52.80   2631    2767   51985   8512     96.2    1.243  ! Near Maximum !
-03.0  103    53.35   2658    2824   53688   8592     96.6    1.226  ! Near Maximum !
-02.0  104    53.90   2685    2881   55445   8670     97.0    1.208  ! Near Maximum !
-01.0  105    54.45   2711    2938   57263   8744     97.3    1.191  ! Near Maximum !
+00.0  106    55.00   2738    2996   59145   8816     97.6    1.174  ! Near Maximum !
+01.0  107    55.55   2765    3055   61093   8885     97.9    1.158  !DANGEROUS LOAD-DO NOT USE!
+02.0  108    56.10   2791    3114   63110   8951     98.2    1.142  !DANGEROUS LOAD-DO NOT USE!
+03.0  109    56.65   2818    3174   65199   9014     98.4    1.126  !DANGEROUS LOAD-DO NOT USE!
+04.0  110    57.20   2844    3234   67364   9073     98.7    1.110  !DANGEROUS LOAD-DO NOT USE!
+05.0  111    57.75   2871    3294   69607   9129     98.9    1.095  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba    106    55.00   2859    3267   69974   8696     99.9    1.095  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    106    55.00   2577    2655   48639   8529     91.5    1.277

[Para Cassatt]

I'm new to the site but have been reloading about 10 years. My preference leans toward compressed loads for the safety of it. An example is the Nosler recipe for the 8x57 mauser of 52 grs. IMR 4350 w/200 gr. Partitions which is a Max. load and the most accurate in manuals 4,5 & 6. The only rememberance of dangerous compressed loads that I can think of was back during the 458 Win. Mag. problems in Africa when they would fail to fire properly.

[Slamfire]

Well I have egg on my face.

I thought it was a straight forward question about compressing powder.

Now, it turns out, it was about learning how to use the correct reloading data with the correct bullet.

Reminds me of that computer support person. The customer was having problems powering up their computer.

Seems the customer had inserted the power strip plug into the power strip.

[briandg]

At least when I first started loading, a compressed or nearly full case was considered best for accuracy, especially extruded powder. The powder would almost form a solid yet porous mass, and ignition of every particle consistently was supposed to happen.

the reasoning behind the PPC and other wide body cartridges are similar, the powder is supposed to ignite far more consistently since the primer flame isn't having to travel as far.

[Dannyl]

deleted

[Nevmavrick]

An excellent example of WHY we start low then go up is what azar92 said...He ran two charges through Quickload and came back with about 2000psi more for 10.5gr of powder at a point that was already higher than safe. It, of course, was WAY past full, so wouldn't have been tried.
The answer is a misprint. It can happen with the internet, and can ALSO happen with printed material, even with a lot of proofreading
Have fun,
Gene

[wncchester]

"When is a compressed load dangerous?"

When it's compressed Bullseye.

[sc928porsche]

Compressed loads should be approached with caution. Start low and work your way up!

[azar92]

Oops! It should have read 57.5 (not 67.5). Typos definitely do happen!