Specific Reloading Questions - 243win

[mick miller]

If your time is limited, and you don't want to read through all of this you can simply scroll to the bottom and see my list of questions, thank you all for your time and input. This is also posted elsewhere on t'internet, why I didn't ask here first I don't really know.

I've recently joined a rifle club as I wished to start developing my own home loaded ammunition having always experienced slightly disappointing results with factory ammo. The idea was to have somewhere I could safely test my loads at various ranges and check the predicted drops over distance with real world results.

As most new to reloading will be aware, the start up is a minefield of conflicting advice and materials. Throw away comments such as 'check for signs of pressure' without any real guidance at to what they are. Also, conflicting advice when it comes to developing loads such as; start low and work up, don't go beneath stated minimum loads, go 10% under minimum and work up, don't go over maximum loads, cross reference loads from at least two sources of data (but no advice of what to do when those sources contradict each other!)

I asked some of these questions and my findings elsewhere and got picked apart and accused of being unsafe and cavalier, so I'm hoping that the replies here will be more balanced, helpful, appreciative of my lack of knowledge and accept that above all, I'm trying to be safe.

I shoot 243win (amongst others but this is the rifle I'm developing loads for). It's a Browning X-Bolt with a hunting type barrel, not a heavyweight varmint or target barrel, as such I have discovered it prefers a load at the low to middle part of any recommended data.

I started with using Vihtavouri data and Viht N150. I chose this because Vihtavouri's own data showed that it could suit bullets from 70gn all the way up to 100gn (see here: http://www.vihtavuor...winchester.html ). As I wanted to eventually develop various loads, specifically for a 100gn Sierra soft point for stalking and a 70gn Nosler ballistic tip load for foxing, I thought it was a good choice.

I sought advice from a knowledgeable source and was advised to start at 10% under start load and work up. As it happens this was very, very good advice. It did rather contradict the advice elsewhere to NEVER GO UNDER RECOMMENDED MINIMUM as this is dangerous and likely I will kill myself, or worse still, those around me.

Viht's data stated a starting load of 41.2gns. and a maximum load of 45.5gns. Using the advice to start 10% lower I loaded several rounds in half grain steps. So:

37 • 37.5 • 38 • 38.5 • 39 • 39.5 • 40 • 40.5 • 41 • 41.5 • 42 • 42.5 • 43 • 43.5 • 44 • 44.5 • 45 • 45.5

Headed off to the range...

My findings where that the best group by far were at 39.5gns - by the way, this was the best group I had ever gotten from this rifle, literally 5p groups of four shots over 100 yards. The best factory ammo had provided to date were 2.5" groups.

But this is under the Viht data for a starting load. Although it still represents 73.4% of case capacity. Note that at 42gns I started to get the signs of over pressure. The bolt was getting hard to lift and small shiny marks appeared on the case base from the ejector pin. Being new (and slightly naive) to reloading I soldiered on to the 43.5gn mark and there I stopped. The bolt was very heavy to lift, marks more pronounced. I figured this was getting unsafe and anyway, the groups were terrible!

So here I have a load that is accurate, but beneath manufacturer starting load data. I also have tried a load just half a grain higher than recommended start load that evidently was over pressure IN MY RIFLE.

I went away and did some more thinking and decided that I would change powders, one that gave a higher fill ratio, but would still permit me to use the same powder for the Sierra 100gn bullets. Why did I do this if I had an accurate load in N150 you may ask? Well, it didn't look like the Nosler ballistic tips were expanding as well as they could. According to the Nosler page, maximum expansion would occur at 3000fps and higher. I was provided data that suggested with my VIHT load, barrel and bullet I could expect sub 2900fps.

***At this point I must admit to not owning a chrono. But, I have since borrowed one and will be testing the original load to establish what the real world data is***

I decided to use Nosler's load data for the 70gn ballistic tip bullets in 243 (see here: http://www.nosler.co...243-winchester/ ) in combination with IMR 4350. This states a starting load of 43gns and a max load of 47gns. I didn't cross check this anyplace else. I also didn't go 10% under the starting load as I had been told, several times, don't go under the minimum load.

I chose IMR 4350 as I had data across the board from Nosler from 70gn to 105gn. I also had load data from Sierra for the 100g soft points that gave a nice spread of powder charges to try, which would give different speeds. I worked out that to get a deer legal round for .243win I need a 100g bullet to at least hit 2800fps to have the required 1700 ft/lb of muzzle energy (see here: http://basc.org.uk/cop/deer-stalking/ ).

So one powder covers a variety of loads, although IMR's own data only starts at 85gn bullets. I'm not sure if that is because it's unacceptable in 70gn or more likely as for them to list every powder in every bullet combination would take years to complete.

I loaded the 70 grainers up with the following charges:

43 • 43.5 • 44 • 44.5 • 45 • 45.5 • 46 • 46.5 • 47

And headed off once more to the range...

My finding were that between 43gns and 44gns produced the best groups with easy bolt lift, no marks on the case head. Everything over that opened up more and more. I did fire two rounds at 47gns. The grouping was awful, the bolt heavy to lift and everything from 45gn up started to leave tiny, but visible shiny marks on the case head from the ejector pin.

So, I noted everything down and came home. Then I got the advice that data should be cross checked before loading and that data published only suits THAT RIFLE on THAT DAY with THAT COMBINATION etc. Which kind of contradicts the other advice to only use published data, not go under minimum or maximum loads, use manufacturer data etc. etc. (One wonders which is correct and which isn't?)

So, I looked at the nearest alternative data I could find for IMR 4350 and 70gn bullets. My Hornady book had nothing, so I used the Sierra Blitzking data (see here: http://accurateshoot...ierra243win.pdf ). A slightly deeper seating depth than I was using (I used Nosler's 2.680", Sierra Blitzking's suggest seating at 2.670"). Now, that suggested a starting load of 41.6gns with IMR 4350 and a max load of 44.6gn!!

Bear in mind in started at 43gn and went up to 47gn. That's quite a bit over the Sierra max of 44.6! And, not surprisingly, I started to notice those little marks on the case head at 45gns.

So, my apologies for a long a detailed post, but I want to provide all the data I've used so far, why I did what I did and ask some questions which I hope will get cleared up to some degree.

Firstly, I've now learned to cross check load data from more than one source. That was good advice. I've also learned that if I ever see those little shiny marks on the case head after extraction TO STOP THERE and go no further. Finally, I've learned that I need to use a chrono with every load, but I'm not sure what, other than the fps, that will tell me.

And so, my questions are:

1). If two data sources are cross checked, do you start at the lowest charge provided by the data despite that being beneath the other source recommending that that is the safe starting point?

2). Should you start under the lowest charge weight you can find, say by 10% (remember that in the case of the Viht data I used this proved to be a safe course of action).

3). If you are testing the loads and getting worsening groups, should you try and shoot through to see if they tighten up again, provided that there are no signs of problems or having shot an over pressure load?

4). Or should you simply stop as soon as you get a tight group and go back and work loads at .3gn intervals either side of that?

5). Are half grain intervals acceptable when first working up a load?

6). What, other than fps, does a chrono tell me. Should I look to see if my load at a given grain weight closely matches the manufacturer data. And if it is higher or lower what does that tell me?

7). Given that I have data for IMR 4350 and a 70gn bullet from two sources, and one of those sources states a starting load of 41.6gn. And given that my best load for this bullet was at 43gns. Is it worth me now loading some test rounds at lower than 43gns. So maybe the next batch to test should be: 42.4 • 42.7 • 43 • 43.3 • 43.6 • 43.9

Well done on getting though all of that. Please can the answers be provided with the corresponding number in front. So if you can answer question 5 please put 5) in front of the answer to save me any more confusion!!

Edited February 4, 2015 by mick miller

[Dougy]

I've read through it all briefly and think i can safely answer a few of the questions. When I get on a pc.

[Underdog]

The general rule of 10% under is for Max listed charge, not listed minimum. It is not even a rule!

 

Pressure signs are a primer as flat as a pancake after firing. Another standard way of checking for pressure is to measure the brass head just above the rim before and make note, fire it and measure again. You don't want more than .004" expansion.

 

Extractor marks don't count.

 

Do make sure your chamber is dry. This does not let the case grip the chamber wall to well and that can load the bolt.

 

You can shoot through an opening up group and it tighten up again. Some of my most accurate groups have been from light barrels. Heat upsets them not pressure.

 

Finding a load for your barrel is about the harmonics of that barrel. As it vibes you are looking for it being in the same place every time that bullet leaves.

 

Not enough pressure from the stock or if free floated and not enough clearance will upset those harmonics!

 

H4350 is great in 243, I hope the imr version is the same.

Is it small sticks, squashed balls or tiny cylinders?

 

U.

[mick miller]

It's small sticks U. Why don't extractor marks count? I looked here: http://www.massreloading.com/reading_pressure_signs.html

 

The marks I got looked like the starting stages of case head extrusion, although no bumps where the brass is flowing into the pin hole, but just a little shiny area corresponding to where the pin sits?

Edited February 4, 2015 by mick miller

[mick miller]

Thank you Dougy, your experience is appreciated.

[Dougy]

Some other thoughts to throw in the pot are,

 

Different bullets designs will have a different effect on powder weight and pressure, something to do with bearing bullet contact on the barrel. hence different books from different bullet manufactures read differently, also time has changed and changes have been made, just compared the same companies versions from 5 years ago for example, they may read slightly different.

UD i slightly disagree regards to marks on the case base, add that to a slightly tighter than normal bolt lift and you are reaching excessive pressure.

You can go through the bad group stage and then find a second node but if velocity is not really needed IE; hunting loads then why bother, i doubt that the energy would be far off 1700 ft/lb

I would agree with higher velocity if you were intent on long range stuff and velocity is required to stay within the stable speeds of the bullet, but 800 yards + is not in this topic.

 

0.5 grains are good enough.

 

chrono,s will show you velocity as you know and velocity spread over your shots but will it really matter to you unless your going long range, i really don't think so. For long range stuff velocity spread will need to be as small as possible as the obvious change in velocity will effect the POI, how much i dont know off hand.

Primers could also alter the group size, as will seating depth of bullets ( i will await the comments re seating depth, and ignore lol)

 

 

Mick If i were in your boots and you get clover leaf groups at 100 yds i would stop, make a note in your reloading book of all the measurements and components, sit back and pat yourself on the back, put the kettle on and have a cupa

 

 

Oh i appreciate the comment re "Experience" but i really am not that much of an expert more an egg spurt

Edited February 4, 2015 by Dougy

[mick miller]

Fair play Dougy. I think, in this case, I'll try a couple more loads in .3gn either side of the 43gn mark with IMR 4350 and see what happens. Measure the best two loads over the chrono (that's the N150 @ 39.5gn and whatever proves best in IMR 4350) and as you say, sit back and pat myself on the back.

 

The seating depths I tend to use whatever the manufacturer suggests for that bullet. I have heard about finding the 'lands' and coming back from that point in small increments but, as I'm not chasing a gnats eyebrow at 800 yards, I think this may make little difference to me, although clearly it does alter the pressure.

 

The only thing I have invested in is the OAL case holder for my vernier. I'm intending to use this instead of measuring the COL from tip to base as this varies depending on the condition of the tip. My plan is to take ten I've loaded with the Nosler's, measure them, average it out, and just make sure that anything else I load measures the same.

 

As for noting the information, yes, I have done that for the first load, my notes are pretty anal, even by my standards!

[Dougy]

 

 

As for noting the information, yes, I have done that for the first load, my notes are pretty anal, even by my standards!

 

I thought they might have been

 

Yes bullets vary a little in OAL its OK to measure the full length, but if you start loading close to the lands then a buy a new batch of bullets could jam in and increase pressure, your better off using the Ogive as a measurement using the OAL gauge

Edited February 4, 2015 by Dougy

[Underdog]

Sounds like the imr is the same as h4350, this is a good thing.

 

Gents I emphasise the importance of a dry chamber. Cleaning fluids or other can increase bolt thrust falsely indicating pressure. Measure the brass head diameter first and after. Under .004" is go.

 

U.

[mick miller]

I did this with the previous load, although I compared factory unfired and fired to my own once fired and resized to fired (this is with the N150).

 

I got (average): unfired Hornady 75gn 0.4637" Fired 0.4677" My loads resized & unfired 70gn 0.4642" Fired 0.4676" So a difference of 0.0034"

 

I didn't do this with the IMR 4350 load yet, as I ummm, resized them all and reloaded the day I got back. Ooops.

Edited February 4, 2015 by mick miller

[neutron619]

0. First things first - reloading has the potential to be dangerous, but it really isn't as unsafe as a lot of people here try to make out - please remember this. It's a simple process and there are basically only two ways you can **** up - too much powder or wrong powder. Most accidents / disasters are variations on this theme in one way or another.

 

Provided you are cautious, pay attention to what you're doing, both when loading and firing, and take advice when you aren't sure rather than trying to "blag" it, there's very little risk of anything unpleasant happening. You can do some quite unorthodox things - certainly stuff that would have a lot of people up in arms here - and be perfectly safe, provided you think through the consequences of what you're doing before you attempt it. Pistol powder in rifle cartridges? Check. "Under-loaded" spherical powders? Check. All my arms / legs / eyes / friends / rifles left? Check.

 

Remember: the reason that a lot of people scream about someone doing X, Y or Z is because they have been taught to understand reloading "religiously". For most people - that's the safe way - because they're following the steps in the process and understanding the consequences of powder grain geometry on burn rate isn't something their brains do easily. Equally, they're right to shout a warning - they'd be irresponsible if they didn't - but remember that much of what you hear will be dogma repeated from books by people who don't fully understand the reasons they're saying what they're saying.

 

You've just told us, after all, that you under-loaded some rounds and - shock, horror - you didn't blow yourself to bits. If you're sensible, your alarm bells will start ringing long before you load or fire a round that is going to kill you.

 

1. Entirely up to you and to some degree what you're trying to do. If you know you want a screamingly fast, flat foxing load then you probably aren't interested in the lower end of the charge range so start at the higher of the two minima and work from there - you'll be ok. On the other hand, if you're trying to reduce recoil and barrel wear, less velocity is a good thing, so try the lower minima.

 

The only thing you need to watch out for is that the two ranges published should be simillar. If one says 40-45gr and the other one says 55-60gr, then your second minima is above the maximum for the first set of data - this should start alarm bells ringing. If it says 40-43gr in one manual and 41-45 in the other, then provided you stay within the "outer" range and watch out for the usual signs to stop, you'll be fine.

 

2. No - in general, start at the published minimum. As I've replied elsewhere, possibly to one of your other threads, you can "under-load" rounds to some degree, but it depends on a lot more factors - what case, what powder, what shape the powder grains are and A lot more besides. If you're going to try under-loading, take advice first and don't deviate too far from the published data unless you're sure you know what you're doing.

 

Replies to 3-7 to follow.

[Dougy]

Sounds like the imr is the same as h4350, this is a good thing.

 

Gents I emphasise the importance of a dry chamber. Cleaning fluids or other can increase bolt thrust falsely indicating pressure. Measure the brass head diameter first and after. Under .004" is go.

 

U.

 

 

Yes UD regards dry chamber. Its amazing how water seems so pliable, and so unimportant until you try tones of force to try and compress it. It just wont, and something else will give before that little chemical or seemingly harmless drop of rain.

 

IMR is listed different to H4350 in all reloading manuals i have UD

[mick miller]

IMR 4350 is different to H4350 and AA4350, but they are extremely close on the burn rate chart I have (almost one above the other). That clearly doesn't mean I can simply substitute one for the other though! (and indeed, I haven't).

[neutron619]

3. Yes, this is perfectly fine provided, as you say, that you don't see pressure problems. I would advise you to be more cautious when approaching the published maximum and look increasingly carefully at the cases, bolt stiffness and the like, but it's always worth a go to see if you can find the next accuracy "node". It may of course be out of reach, but if you can go through the whole powder range, do.

 

Furthermore, I can't, won't and don't advise you to exceed a published maximum, but you are probably aware by now that there are people who do without killing anything other than the deer / fox / other that they were aiming for. Generally, higher pressure loads for a given cartridge tend to be more accurate, but it's not a rule - more a general guide. Most importantly, wherever you stop - it's your risk after all - remember that faster bullets wear out barrels a lot faster and do a lot more damage to a carcass.

 

It's my personal prejudice - please ignore it - that once you get to about 2800-3000fps, if still you're chasing higher energy, then you should be switching up a bullet size and dropping the velocity back again, particularly if you want to eat what you're killing. In fact, I'm rather hoping that a very heavy-for-calibre .308 round I've been developing will produce the same energy of a normal factory .308 round, but with an MV of 2250fps or so - the theory being a clean hole from side to side and knowking them over, rather than the usual "total mangling" of a BT bullet at 3000fps turning the deer's innards to soup. We shall see.

 

4. Refinement is great, but it depends what you're trying to achieve. Smaller and smaller groups can be a great hobby / obsession / etc. but if you're not trying to kill foxes from 500 yards, then anything sub-1" @ 100yd is good enough. Most people can't shoot as well as that and if you've been testing them outside, it's quite possible that your ¼" groups are a product of changing air density, unstable resting point or any other number of things. (I'm sure they aren't, but you see what I'm saying about external influences.)

 

If you shoot to reload, it's one thing, but ultimately, if you just want a reliable round with a XXXgr bullet you only need to go so far - if your 40gr round shoots half an inch, leave it. Also remember that scales and measuring equipment are only accurate to a certain degree. Your 40.0gr may in fact vary between 39.8gr and 40.2gr (extreme example), so smaller and smaller increments may find the best "mid-point" for your round, but they won't eliminate variation entirely.

Edited February 4, 2015 by neutron619

[neutron619]

5. In your case - .243 Win. - probably, and at the lower end of the charge scale I'd even be tempted to use 1.0gr increments, depending on the powder. In a .22 Hornet though, they'd probably be far too big, and in a .300 Weatherby taking 80-90gr of powder, you'd die before you got to the end of the ladder. The key is look at the range and be sensible.

 

If you're working from 38gr to 46gr as a published range, then the chances are that doing the first few steps in 1.0gr increments will be fine. You've clearly got a powder there where pressure increases relatively slowly with powder mass. In that case, I might try:

 

38.0, 40.0, 41.0, 42.0, 43.0, 44.0, 44.5, 45.0, 45.5, 46.0

 

doing one or two rounds at the earlier charge levels and then three or four for the latter.

 

On the other hand, if your powder range is 44.0-46.0gr, you have a powder where pressure increases very quickly through your range, so a 0.5gr increment will be too large - I'd probably use 0.2-0.3gr increments there.

 

Look at the "length" of the range and divide it by 8-10 - that's probably your increment. Work up more quickly at the bottom and more cautiously as you approach the top. Don't go over the top with the number of rounds - your first job is to identify your safe maximum. You can refine for accuracy later.

 

6. A chrono will tell you (indirectly) the ballistic coefficient of the bullet as you've loaded it, which in turn will give you the trajectory and accurate drop / deviation calculations if you know the conditions.

 

7. Experimentation is the only way you'll answer your question for sure. If you have the time, energy and inclination, go for it. Apply all the usual safety precautions and shoot carefully - it may give you an even better result.

Edited February 4, 2015 by neutron619

[neutron619]

It's small sticks U. Why don't extractor marks count? I looked here: http://www.massreloading.com/reading_pressure_signs.html

 

I suspect - I await U's answer with interest - that this refers to the possibility I've discussed recently elsewhere.

 

The cases of low pressure, deliberately under-loaded rounds can fail to expand to obturate with the chamber walls upon firing. This means that there is little friction between the outside of the case and the chamber wall, causing it to act like a rocket and slam back into the bolt face, printing the mark of the extractor groove on the headstamp.

 

However, this is an extremely rare situation and will be expected by anyone loading in this way, so I agree with Dougy in principle - if you're seeing extractor marks on the brass and aren't expecting it, I'd stop. Certainly if you see this sign in combination with any other - flattened primers, stiff bolt lift - that's a sign of excess pressure.

[mick miller]

Thank you Neutron, Dougy et al.

 

The shiny marks were at the upper end of the powder load. In the first case with N150 this was as I reached the 42.5gn - 43gn range. That represents (working on a 51gn h2o fill) a near 83% capacity fill. With the IMR 4350 again, the upper end where I neared 98% case capacity.

 

Thank you all for answering the questions by number. I will print this off and collate it all later to add to my notebook.

Edited February 4, 2015 by mick miller

[aris]

Just curious - which rifle ranges do .243 in HERTS?

Edited February 4, 2015 by aris

[Dougy]

Reading Neutrons replies I think you should both get together over a pint, I for one would get the first round in, I would expect it to be a very interesting evening, Oh ! and UD of course I would get you one as well

[Underdog]

In my experience and in no way do I wish to subtract from others, the ammunition is consistent in a relative way, compared to a rifle! More accuracy issues can stem from the rifle over the ammo. Let me explain that. One lug on the bolt doing nothing, bad bedding, bolt handle touching the stock and the barrel rattling on the forestock, bad crown or bad scew cutting will make finding a satisfactory load a chore!

Those issues eliminated is the only time we can turn on the ammo!

I have found I can tell when a load will struggle just by recoil! Don't read into that statement too much!!

Any load that the gun comes straight back every shot is going to be reasonable. If any irregular sensation of the gun jumping around or odd sideways movements and it is going to struggle! Sounds nuts but I find it true. Not always at first but later it may just be noticed if one goes over the firings in your mind!

 

OK, got my flame suit on!

 

U.

[mick miller]

Just curious - which rifle ranges do .243 in HERTS?

None! Who said it was in Herts?

 

You have one at Barton Road and another at Thetford.

[Mutiny]

Some great information in this thread, it's been really interesting & informative for me as a current non-reloader looking to get started in reloading

[neutron619]

Reading Neutrons replies I think you should both get together over a pint, I for one would get the first round in, I would expect it to be a very interesting evening, Oh ! and UD of course I would get you one as well &&0

 

Just saw this. Always happy to do so if it's helpful, but I'm not an expert by any means - just a tinkerer...

[mick miller]

Oh right, well I am trying a new load with n140, it seems more suited to the lighter bullets.

[neutron619]

Oh right, well I am trying a new load with n140, it seems more suited to the lighter bullets.

 

Makes sense - lighter bullet = less resistance in barrel so a faster powder will work without going over maximum pressure. In theory, anyway.

 

I'd be interested to hear how you get on, if you have time to update the thread when you've tried them out.