Muzzle energy

Richard S

Well-Known Member
I am a novice reloader, and following the recent thread about the use of a chronograph (an instrument I do not have) I have been trying to determine the velocity required from my loads to obtain a deer legal muzzle energy of 1700 ft.lb.
It seems from the tables I have, and using a calculator I found on the web, that such a velocity can only be provided by loads in the mid to upper reaches of the range.
My question is therefore, what is the point of starting from the lowest end of the scale, as normally recommended, when working up a load if it doesn't produce a legal muzzle energy? Would it not be more practical to start somewhere in the middle ?
I would be grateful for any advice.

Richard
 
It's a safety thing mate. Your rifle will have different internal dimensions to the test rifle used in producing the load info for the book. The 243 (I assume you are talking about this calibre) is marginal for power as you have already mentioned. The writers of the load data don't care about UK deer legislation.

I used a 243 for a few years. I found the best medicine for deer with a 243 was a Sierra 100gn GameKing, trotting along at around 3000fps.

Everything I pointed it at died...some more quickly than others.

ATB
 
I am a novice reloader, and following the recent thread about the use of a chronograph (an instrument I do not have) I have been trying to determine the velocity required from my loads to obtain a deer legal muzzle energy of 1700 ft.lb.
It seems from the tables I have, and using a calculator I found on the web, that such a velocity can only be provided by loads in the mid to upper reaches of the range.
My question is therefore, what is the point of starting from the lowest end of the scale, as normally recommended, when working up a load if it doesn't produce a legal muzzle energy? Would it not be more practical to start somewhere in the middle ?
I would be grateful for any advice.

Richard

It is all about working the load up and looking for pressure signs on the case. A safety procedure.
The only way to tell if your ammunition is compliant is with a chrono.

Enter the squeals of anguish from 'the deer can't tell' 'no ones ever been checked' etc etc. Simply put you need with 100gn bullet >2770fps to comply in England.
 
Thanks for the replies,

Yes, it is for 243. It does seem that I am looking to achieve around 3000fps for a 95 grain bullet and a little over for an 87 grain. To reach this I expect I will need somewhere around 42 grains and 40 grains respectively of N160.
I have been loading 38.1 grains which group well, but I now realise are falling way below required muzzle energy. I know from another thread that others are using around 44 grains for similar bullets, so I am now proposing to start working up from 40 grains for the 95s. I don't want to appear to be a cheapskate or to be cutting safety corners, but also I don't want to make up and fire dozens of rounds which I know will not achieve the required energy.

Does everyone else worry about checking the 1700ftlb ? I realise as JB has said that it can only be checked accurately with a chrono, but for me , and I'm sure many others, this is not an option.

Am I making too much of this ?

Richard
 
Thanks for the replies,

Yes, it is for 243. It does seem that I am looking to achieve around 3000fps for a 95 grain bullet and a little over for an 87 grain. To reach this I expect I will need somewhere around 42 grains and 40 grains respectively of N160.
I have been loading 38.1 grains which group well, but I now realise are falling way below required muzzle energy. I know from another thread that others are using around 44 grains for similar bullets, so I am now proposing to start working up from 40 grains for the 95s. I don't want to appear to be a cheapskate or to be cutting safety corners, but also I don't want to make up and fire dozens of rounds which I know will not achieve the required energy.

Does everyone else worry about checking the 1700ftlb ? I realise as JB has said that it can only be checked accurately with a chrono, but for me , and I'm sure many others, this is not an option.

Am I making too much of this ?

Richard
It is up to you what corners you want to cut and I'm not advising that you do, generally the advise is 'work up carefully' use the opportunity to get some trigger time too. You might want to stick with factory stuff if you are not feeling comfortable reloading.
Most do not bother with checking their velocities, I do, of course this will change with the first test done by forensics laboratories......
 
Thanks Joe,

It's not that I'm not comfortable with reloading, and obviously more experience is necessary. I'm just interested in the performance of my loads apart from grouping, as that seems to be the usual criterion for a successful load.

Richard
 
It's your decision mate. There is no grey area, you either comply or you don't.

As for where you start load development, that is also up to you. I no longer use a load manual for anything other than seeing where they peaked out at the top end and even that is only a guide since I load considerably longer than the book COAL. I noticed that when I started out that generally speaking the best load to be had was in the upper half of the suggested load range. However you must understand that your rifle may experience considerably higher pressure with a lot less powder than the test barrel used for the book.

It's your face and your eyes sat behind the chamber when the overpressure occurs, so once again it's your choice on whether the risk is worth saving a few £ against losing eyes, fingers or life.

You don't need to make up dozens of rounds. I start at the beginning fire a single round over the chronograph and move up in .5gn increments for the 270 and .3gn for the 223 and see where I sit with regard to the advertised velocity. Remembering there is no such thing as cold fusion, I want to be in the ballpark. If I see a high velocity then I'm probably getting that with higher pressure. I then proceed accordingly.

When I have a good baseline for the rifle I then switch to the OCW method and go from there.

ATB
 
for me this is simple

you know what charge you need for a specific velocity (even the VV data will give you a rough idea, and you have seen what others are using)

Any loads below that are of no value to you and the only reason you are loading them is to prove they do not show pressure in your rifle.

I load ONE round of any charge between minimum and the level at which I have decided I want to start load testing, purely to check for pressure signs.

If I where you I would be doing
38grx1, 38.5grx1, 39grx1, 39.5grx1, 40grx3, 40.5grx3, and maybe 41grx3, beyond that you are on your own,
you can use smaller increments if you wish but you are trying to reach a charge level safely.
if you then wanted to tweak 40.2, 40.4 40.6, 40.8 etc that is up to the accuracy they show and how anal you want to take it

I personally would take it further to ascertain the max for my rifle
but I am not going to suggest you do this without someone with more experience with you to check the cases and reactions

Lets not be melodramatic about it
Overpressure happens a lot!! people don't tend to lose eyes and fingers from putting 0.5 or even 1gr of (the right) powder too much
Rifles are built and proofed at much much higher levels than the normal reloader will ever see. (the proof house go out of their way to use much more in the way of overloads with heavier bullets)
you might get a stiff bolt, a flattened primer, a extractor mark on the case head.

Without looking at quickload or any other app I am pretty confident with a standard barrel a 40gr charge will get you over the required MV
sure someone else can confirm this

VV max data for 90gr is 44gr N160 and around 3100fps
max data for 100gr is 38gr N160 and 2964fps

2840fps with 95gr gets you over the required ME
 
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The problem Richard is that the .243w round only just meets minimum legal requirements for larger deer using most factory ammo in a rifle with a reasonable length barrel. Reloading data is sometimes hyped up slightly and anyway it is shot in a test barrel normally.
Until you run your loads over a chronograph you will never now for certain what velocities and muzzle energies you are actually achieving, at best you will only have a rough guess. If you are genuinely concerned and you don't have access to a chronograph drop me a pm and we will see if we can sort out a trip over to Monmouth where for a small range fee you will be able to run your loads over the chronograph on the indoor range.
 
Lets not be melodramatic about it
Overpressure happens a lot!! people don't tend to lose eyes and fingers from putting 0.5 or even 1gr of (the right) powder too much
Rifles are built and proofed at much much higher levels than the normal reloader will ever see. (the proof house go out of their way to use much more in the way of overloads with heavier bullets)
you might get a stiff bolt, a flattened primer, a extractor mark on the case head.

If I may, I assume this remark was aimed at me. If not I apologise, but he never suggested going up in .5gn increments or even 1gn. He suggested he went from 38.1gn to 40gn in one step. IME a 5% increase is daft as a novice re-loader and does risk fingers, eyes etc.

I saw the remains of a mates Rem 17 that was the result of simple inattention to detail. He never calibrated his scale and it caused it to fail with a simple overcharge.

As I'm sure you know, all bullets of equal weight and calibre do not generate the same pressure. E.g. Berger list 95gn VLD at a max charge of 43.9gn N160 conversely QL is only happy until you get to 43.6gn of the same powder. VV list a 90gn Scenar at 43.7gn N160 max. QL ,OTOH is happy until you get to 44.3gn N160. Nothing about load data is cast iron no matter how it's presented.

Therefore, guessing a random start point from peoples claimed safe load data is a recipe for disaster, especially for a novice who may not know his rifle or what would be an obvious warning sign to an experienced re-loader.

ATB
 
The problem Richard is that the .243w round only just meets minimum legal requirements for larger deer using most factory ammo in a rifle with a reasonable length barrel. Reloading data is sometimes hyped up slightly and anyway it is shot in a test barrel normally.
Until you run your loads over a chronograph you will never now for certain what velocities and muzzle energies you are actually achieving, at best you will only have a rough guess. If you are genuinely concerned and you don't have access to a chronograph drop me a pm and we will see if we can sort out a trip over to Monmouth where for a small range fee you will be able to run your loads over the chronograph on the indoor range.

Have to call 'bull' there!
I have no problems reaching and exceeding the legal requirements with 243 win.

(lead free load 85gn @ 3350 - 2118ft lbs)
 
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If I where you I would be doing
38grx1, 38.5grx1, 39grx1, 39.5grx1, 40grx3, 40.5grx3, and maybe 41grx3, beyond that you are on your own,
you can use smaller increments if you wish but you are trying to reach a charge level safely.
if you then wanted to tweak 40.2, 40.4 40.6, 40.8 etc that is up to the accuracy they show and how anal you want to take it

Thanks,

That seems like sound practical advice which I will follow.

​Richard
 
If you are genuinely concerned and you don't have access to a chronograph drop me a pm and we will see if we can sort out a trip over to Monmouth where for a small range fee you will be able to run your loads over the chronograph on the indoor range.

Thanks for your offer. I don't think I'll need to do that though. The replies here have crystalised my thinking and I now have a good idea of how to proceed.
I hadn't realised it was such a touchy subject, and hope I have not come across as a gung ho powder monkey. I really am very careful regarding safe practice, which is why I asked the question in the first place.
Thanks for all the replies..

​Richard
 
Have to call 'bull' there!
I have no problems reaching and exceeding the legal requirements with 243 win.

(lead free load 85gn @ 3350 - 2118ft lbs)

You can call it what you like Joe but it's a fact that some factory loads in some rifles barely make 1700 ft/lb and some don't. It's certainly not helped by the fad for cropping barrels. I dare say that you read the article in Shooting Times some months ago by Bruce Potts on the .243w with short barrels. I believe that the conclusion that Bruce came to was that it was unwise to shorten the barrel on a .243w to less than 20" if you wanted to achieve the magic 1700. If you haven't read the article it may well be worth looking it up as it was most enlightening.
You have obviously satisfied yourself that your load in your rifle meets the requirements.
 
You can call it what you like Joe but it's a fact that some factory loads in some rifles barely make 1700 ft/lb and some don't. It's certainly not helped by the fad for cropping barrels. I dare say that you read the article in Shooting Times some months ago by Bruce Potts on the .243w with short barrels. I believe that the conclusion that Bruce came to was that it was unwise to shorten the barrel on a .243w to less than 20" if you wanted to achieve the magic 1700. If you haven't read the article it may well be worth looking it up as it was most enlightening.
You have obviously satisfied yourself that your load in your rifle meets the requirements.

Well reloaded stuff does not have the problem in fact 18" barrel does not appear to be a problem either. Don't waste money on shooting times and do not care much for mr potts either.

FYI - read the OP which was talking about reloading.
 
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Not sure about that Joe. Using a Nolsler 100gn Partition and going to the ragged edge in QL you only get 2728fps and 1653ft lbs...and that's @45.3gn N560 The max book figure is 44.5gn with this powder. That is the fastest load in Nosler's book for that load. A re-loader might just squeak over the 1700ft lbs limit with a fast barrel but I wouldn't bank on it.

The truth is that it's closer to the line in some formats than people think. I suspect many don't know or don't care...until the first prosecution that is.

ATB
 
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Well reloaded stuff does not have the problem in fact 18" barrel does not appear to be a problem either. Don't waste money on shooting times and do not care much for mr potts either.

FYI - read the OP which was talking about reloading.

If you read my first post correctly you will see that I stated factory ammo so stop shouting or you will do yourself an injury.
 
If I may, I assume this remark was aimed at me. If not I apologise, but he never suggested going up in .5gn increments or even 1gn. He suggested he went from 38.1gn to 40gn in one step. IME a 5% increase is daft as a novice re-loader and does risk fingers, eyes etc.

Not aimed at anyone or a personal attack. sorry if it came across that way
Its merely an effort to dispel the "end of the world" scenario of jumping close to max loads.

I am not advocating he makes that jump but even if he was to jump from 38.1-40gr in one go I sincerely doubt the rifle would blow up in his hands or vent hot gas into his face unless there are other SIGNIFICANT issues.
Very confident the proof house put a load through it that would make your eyes water and make 42gr N160 under 95gr look like a starting load before he got his hands on it.

if your mates Rem17 blew up I would be surprised if it was down to "a simple overcharge".
We are not talking about +5 or 10% of a sensible powder for that bullet weight are we?
By sensible I mean his powder choice in a case that size shouldn't allow for a charge increase big enough without running out of case capacity.
I am intrigued to know the details though.

Not trying to make light of hot loads but I make a point of finding the max loads in all my rifles and loads.
Not because I want to sail close to the limit, in fact I would say that pretty much all my loads in all calibres are WELL below max by some margin.

But I want (in fact NEED) to know that my x.xgr load is actually 3, 4 or 5gr less than MY rifle's max,
not 0.1gr less than MY rifle's max and that a trip to shoot bucks in the heat of the south east in July
or a dropped and overly seated bullet isn't going to tip me over the edge.

It's a bit like knowing how fast your car can go round a corner in the wet before it loses traction or how it reacts when emergency braking.
I don't want to find out the hard way by surprise and make sure if know in advance
 
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