Underdog Posted February 18, 2015 Report Share Posted February 18, 2015 Years ago shooting a string of shots testing ammunition. We noticed many times that if the barrel got hot beyond half way the loads were never much good. If the heat was closer to the breech(obviously before to many shots fired) the loads did better. Sounds nuts yes but it is what we have observed many times! Quote Link to comment Share on other sites More sharing options...
neutron619 Posted February 18, 2015 Report Share Posted February 18, 2015 (edited) Years ago shooting a string of shots testing ammunition. We noticed many times that if the barrel got hot beyond half way the loads were never much good. If the heat was closer to the breech(obviously before to many shots fired) the loads did better. Sounds nuts yes but it is what we have observed many times! Possibly due to the malleability of the steel changing under temperature, altering the barrel's harmonics? Beyond halfway, to me, means "the point at which the metal is thin enough for the barrel to be very slightly flexible" as opposed to (effectively) completely inflexible closer to the breech. Thicker metal around the breech would compensate for a change in tensile strength, but if the barrel towards the muzzle were anything like as thin as the one on my Heym, I could well imagine a bit of heating changing the way in which it resonates with the shot. Of course, the same effect in the other direction - i.e. using a "warming" or "priming" shot (can't remember the proper name) to warm a cold barrel before shooting the main group is widely recognised. Edited February 18, 2015 by neutron619 Quote Link to comment Share on other sites More sharing options...
Underdog Posted February 18, 2015 Report Share Posted February 18, 2015 Maybe you have it yes. I wondered if to a slightly later peak pressure was affecting the lighter end of the barre! Kind of similar thing! Quote Link to comment Share on other sites More sharing options...
mick miller Posted February 18, 2015 Author Report Share Posted February 18, 2015 (edited) So in the IMR 4350 tests the best group was obtained with a 43gn charge behind a 70gn bullet. However, some things were noted. Dirty cases suggest only partial obturation of the case, perhaps blackened by burnt powder blowing back around the case neck? So the quest continues. Next trial is N140, a faster powder which means I need less of it. The N150 and IMR4350 now destined to be repurposed for the 100gn soft point bullet. For now I'm using the N150 load in the 70gn BT's. But the N140 should allow me to work something up for both 55gn and 70gn bullets. I think, ultimately, I'll only use two powders and they'll both be viht, it's easy to source, measures well and seems to be the most cost effective of them all. Edited February 18, 2015 by mick miller Quote Link to comment Share on other sites More sharing options...
neutron619 Posted February 18, 2015 Report Share Posted February 18, 2015 (edited) So in the IMR 4350 tests the best group was obtained with a 43gn charge behind a 70gn bullet. However, some things were noted. Dirty cases suggest only partial obturation of the case, perhaps blackened by burnt powder blowing back around the case neck? So the quest continues. Next trial is N140, a faster powder which means I need less of it. The N150 and IMR4350 now destined to be repurposed for the 100gn soft point bullet. For now I'm using the N150 load in the 70gn BT's. But the N140 should allow me to work something up for both 55gn and 70gn bullets. I think, ultimately, I'll only use two powders and they'll both be viht, it's easy to source, measures well and seems to be the most cost effective of them all. I don't really want to start a sentence with the word "QuickLoad predicts..." but here goes: QuickLoad predicts that 43gr of IMR4350 under a 70gr bullet is a very low pressure load indeed. It looks to me like that's either a very light charge, or that powder is on the slow side for such a light bullet. I believe you said the top of the charge range was 47gr - that gives a pressure only a few percent under maximum for the cartridge, so that'll explain the heavy bolt lift you described in your first post. It's strange - burn rate wise, it should be right where you want it, but it "feels" like wrong powder for the cartridge / bullet to me. I'm not a .243 user though, so don't quote me on that. Having said that, I'd like to make helpful suggestions here if I can, but I'm finding it hard to follow which loads you currently have that are acceptable? If I've understood right, you have: 100gr SP over 39.5gr Vit N150 - quite a hot load by the look of it, but should be giving you 1800+ ftlbs so it'll do for deer if it's accurate. 70gr BT over 43gr IMR 4350 - a very mild load with poor case-to-chamber obturation probably giving around 1500ftlbs What I suggest depends on what you want to do. If you want one powder that works for a 70gr and a 100gr load, I'd be looking at something like H414 or Vit N550. From my calculations, they should be "middle-of-the-road" enough to push your 100gr bullet at deer-legal velocities, but still drive your 70gr bullet to around 3200fps meaning you get the expansion on Charlie that you need. There are better powders if you want to push one or the other load to its maximum potential velocity, but the two above would be a "one pot fits all" solution. The Lee manual seems to match up pretty well with what QL is predicting on this, so you have some reassurance in the published data. I'm not going to type the QL data up here because I am in one place making inferences about what will work and I'd prefer that you went off, looked at it yourself and made your own decision. QL also seems to be slightly more "optimistic" about when you'll start to see pressure signs with those powders than the manuals, so it's not really right for me to start putting those numbers online, in case they're wrong. Anyway - hope some of that is helpful. I realise pots of powder aren't cheap and that you can't necessarily get exactly what you want reliably. Edited February 18, 2015 by neutron619 Quote Link to comment Share on other sites More sharing options...
Underdog Posted February 18, 2015 Report Share Posted February 18, 2015 The only time to really worry about case sooting is if it is on the main case body. The neck is not really a worry and an indication of nothing! Believe me, at peak pressure whether high or low pressure that brass will be pressed against the chamber wall! It is just a slower extinguishing flame that's all. Purely based on my experience and finding. No scientific evidence. U. Quote Link to comment Share on other sites More sharing options...
sonicdmb Posted February 18, 2015 Report Share Posted February 18, 2015 Before you go buy a different powder might I ask how many 70 gn bullet you have left. If you don't have many might I suggest a change of bullet, I have a very accurate load with 87 vmax over Hodgdon H4350 which IMR h4350 would be a reasonable substitution. Depending on what species and how many you shoot its not bad for deer either. Might I also suggest that as opposed to 1 grain or 0.5 grain increases I use 1% rounding where necessary this works regardless of calibre. Chronographs do more than help find BC as speed is directly related to the pressure behind the bullet if you get over the published maximum speed for a given load chances are your getting max pressure too. Quote Link to comment Share on other sites More sharing options...
neutron619 Posted February 18, 2015 Report Share Posted February 18, 2015 (edited) Chronographs do more than help find BC as speed is directly related to the pressure behind the bullet if you get over the published maximum speed for a given load chances are your getting max pressure too. No - sorry - this isn't correct. It's perfectly possible to use wildly different powders to push the same bullet out of the same barrel at the same speed, where one powder produces a life-threatening 100000psi+ and the other produces pressure well under the maximum for the calibre. Edited February 18, 2015 by neutron619 Quote Link to comment Share on other sites More sharing options...
mick miller Posted February 18, 2015 Author Report Share Posted February 18, 2015 (edited) Ahh, right. I need to clear a couple of things up here. LOADS Acceptable (by acceptable I mean no sign of over pressure, good groups) Viht N150 39.5gns behind Nosler 70gn Ballistic Tip (clean case, dirty neck but no better/worse than factory ammo good group, 5 click drop at 200 yards - 13 click drop at 300 yards) IMR 4350 43 gns behind Nosler 70gn Ballisitic Tip (however, sooty cases the entire length suggesting poor obturation) PROPOSED LOADS Viht N140 behind Nosler 70gn Ballistic Tip - I have three separate sources of data to use for this Viht N140 behind Nosler 55gn Ballistic Tip - I have two sources of data for this - Faster powder should perform better with lighter bullets - REPURPOSED POWDERS Viht N150 behind Sierra 100gn soft point boat tail - data sources for this IMR 4350 behind Sierra 100gn soft point boat tail - data sources for this - Slower powders should perform better with heavier bullets - Edited February 18, 2015 by mick miller Quote Link to comment Share on other sites More sharing options...
mick miller Posted February 18, 2015 Author Report Share Posted February 18, 2015 It's a shame quick load won't work on a Mac, looks like good software (no I don't want to install windows into a partition, been there, done that - hellish!!). Quote Link to comment Share on other sites More sharing options...
sonicdmb Posted February 18, 2015 Report Share Posted February 18, 2015 No - sorry - this isn't correct. It's perfectly possible to use wildly different powders to push the same bullet out of the same barrel at the same speed, where one powder produces a life-threatening 100000psi+ and the other produces pressure well under the maximum for the calibre. Please note I said published max for a given load as in load is 42gn for 2800fps 45gn for say 3400. you know that if you get 3500 your over speed therefore over pressure for that load. I never mentioned using it to compare two different powders. Quote Link to comment Share on other sites More sharing options...
mick miller Posted February 18, 2015 Author Report Share Posted February 18, 2015 Noted Quote Link to comment Share on other sites More sharing options...
sonicdmb Posted February 18, 2015 Report Share Posted February 18, 2015 N140 is a good choice for lighter bullets I used it with 55 sierras 58 and 75 vmax. Your repurposed powders should work for 80gn up bullets. I used to load fairly fast light bullets I inherited with my gear some Varget Reloader 15 VV N140 and Hodgdon H4350. Basically went through 55 blitz kings some 80 siera softpoints then 58 75 ands finally 87 vmax. The reason behind my now one and only load is I only shoot the odd Roe, but plenty of foxes. The 87 vmax has a BC of .400 so while you have to account for a bit more drop wind is less of a problem. Most rifles are best with their middle weight of bullet mine loves these (so does a mates in fact the exact load). The other reason is barrel life I shot out as in no rifling left in first bit of barrel (still shot well enough) so instead of lots of chopping and changing I went with the 87 the last one used in previous gun. Unless shooting in Scotland you only have to worry about minimum power not bullet weight, is there any reason why not to find a mid weight that will suit for both. Unless your after bigger deer of course then maybe try some 90's or 95's. Just a thought. Quote Link to comment Share on other sites More sharing options...
mick miller Posted February 18, 2015 Author Report Share Posted February 18, 2015 The 100 grainers will be used for Fallow. Everything else is Munties or foxes (75gn). But I'd like a light fast bullet (55gn) just to use on rabbits (not picking them up) and if I see a fox still have the ability to deal with that on one of the other places I shoot over the summer months. Quote Link to comment Share on other sites More sharing options...
sonicdmb Posted February 18, 2015 Report Share Posted February 18, 2015 Bloomin expensive way of shooting rabbits . If your rifle likes them I'd go for 58 vmax nice and flat for rabbits and plenty foe charlie. Before you buy any 100's have a look at what 90/95's you can get hold of (nothing worse than finding a load and not being able to get components) You should find they shoot quite a lot better than 100's and with the right constuction will be good for Fallow and anything else for that matter. Quote Link to comment Share on other sites More sharing options...
neutron619 Posted February 19, 2015 Report Share Posted February 19, 2015 Please note I said published max for a given load as in load is 42gn for 2800fps 45gn for say 3400. you know that if you get 3500 your over speed therefore over pressure for that load. I never mentioned using it to compare two different powders. Apologies - misinterpreted or simply misread what you said. Agree with what you've said. Quote Link to comment Share on other sites More sharing options...
neutron619 Posted February 19, 2015 Report Share Posted February 19, 2015 (edited) Before you buy any 100's have a look at what 90/95's you can get hold of (nothing worse than finding a load and not being able to get components) You should find they shoot quite a lot better than 100's and with the right constuction will be good for Fallow and anything else for that matter. I don't necessarily disagree with any of this, but just to point out to mick that whilst the law doesn't specify 100gr in England / Wales like to does in Scotland, it would be a bit of a ****** if you were offered the trip of a lifetime (e.g. Red Stag in the Highlands) unexpectedly and didn't have a 100gr round in the cupboard (or in the reloading book) that you could make up and use. Personally, I go for heavier / slower bullets every time, but I've said / implied that already and .243 isn't always happy with a 100gr bullet, so it's a bit of a toss up really. Depends what you think you might do and where you might go to do it. Edited February 19, 2015 by neutron619 Quote Link to comment Share on other sites More sharing options...
sonicdmb Posted February 19, 2015 Report Share Posted February 19, 2015 I don't necessarily disagree with any of this, but just to point out to mick that whilst the law doesn't specify 100gr in England / Wales like to does in Scotland, it would be a bit of a ****** if you were offered the trip of a lifetime (e.g. Red Stag in the Highlands) unexpectedly and didn't have a 100gr round in the cupboard (or in the reloading book) that you could make up and use. Personally, I go for heavier / slower bullets every time, but I've said / implied that already and .243 isn't always happy with a 100gr bullet, so it's a bit of a toss up really. Depends what you think you might do and where you might go to do it. Yes something to consider but my cure for that is a box or two of PPU 100's "in stock" they don't shoot anything like as good as my 87gn load (0.3" @ 100 yds) with 1.5" groups but for deer that is enough for me. My foxing can call for much longer shots so for a dual purpose round I'd like to see 1/2" to 3/4" groups. Bullet choice is always a compromise between intended use range and target species, availability and rifles "taste" . I suppose I was lucky that my rifle really likes the load the best group was three shots one each from bipod on flat back on pickup, sand bag off the same and then off quad sticks. I have a load that will do for serious long range for foxes that with careful bullet placement isn't to wasteful of meat on the odd Roe. Zero is something to consider with more than one bullet weight its easy to lose track of what your zerod for, with the potential for a miss or worse wounding. Quote Link to comment Share on other sites More sharing options...
mick miller Posted February 19, 2015 Author Report Share Posted February 19, 2015 (edited) I use Fiocchi 100gn soft points at the moment, they're cheap and group well at 100 yards. I just thought I could make my own 100gn load up for occasional use on Fallow, and that trip of a lifetime (although I think I might have already had that!). Edited February 19, 2015 by mick miller Quote Link to comment Share on other sites More sharing options...
mick miller Posted February 20, 2015 Author Report Share Posted February 20, 2015 (edited) Okay, more reloading confusion!! Although I think I have a fix. So, I bought some N140 to use with the Nosler 70 grainers (also will use for the 55gn too). I have *three sets of data, plus an output from quick load. However, to say it is contradictory is an understatement! Lee Modern Reloading 70gn Jacketed v-N140 Starting load 41.0 (3196fps) Max Load 44.5 (3505 fps) Sierra Load Data 70gn Blitzking v-N140 Starting load 37.4 (3100fps) Max Load 38.6 (3200 fps) Vihtavuori Published Data 70gn v-N140 Starting load 38.7 (3003fps) Max Load 43.2 (3389 fps) Vihtavuori Website Data 70gn v-N140 Starting load 41 (3196 fps) Max Load 44.5 (3563 fps) Plus Quickload N140 Cartridge : .243 Win. Bullet : .243, 70, Nosler BalTip 39532 Useable Case Capaci: 51.115 grain H2O = 3.319 cm³ Cartridge O.A.L. L6: 2.700 inch = 68.58 mm Barrel Length : 24.0 inch = 609.6 mm Powder : Vihtavuori N140 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 82 37.80 3113 1507 43758 8498 100.0 1.178 -09.0 83 38.22 3141 1534 45088 8543 100.0 1.162 -08.0 84 38.64 3169 1561 46454 8584 100.0 1.146 -07.0 85 39.06 3197 1588 47858 8624 100.0 1.131 -06.0 85 39.48 3224 1615 49300 8664 100.0 1.116 -05.0 86 39.90 3251 1643 50781 8704 100.0 1.102 -04.0 87 40.32 3278 1670 52303 8742 100.0 1.088 ! Near Maximum ! -03.0 88 40.74 3304 1697 53867 8781 100.0 1.074 ! Near Maximum ! -02.0 89 41.16 3331 1724 55473 8819 100.0 1.060 ! Near Maximum ! -01.0 90 41.58 3357 1751 57124 8856 100.0 1.047 ! Near Maximum ! +00.0 91 42.00 3383 1779 58820 8893 100.0 1.033 ! Near Maximum ! +01.0 92 42.42 3408 1806 60563 8929 100.0 1.020 !DANGEROUS LOAD-DO NOT USE! +02.0 93 42.84 3434 1833 62355 8965 100.0 1.008 !DANGEROUS LOAD-DO NOT USE! +03.0 94 43.26 3460 1860 64196 9001 100.0 0.995 !DANGEROUS LOAD-DO NOT USE! +04.0 95 43.68 3485 1888 66088 9035 100.0 0.983 !DANGEROUS LOAD-DO NOT USE Given that my rifle has already shown that the upper end of the scale results in sign of having fired an over pressure load, I'm erring on the side of caution here. I intend to make 9 batches of 4 completed rounds. At these powder charges (which is calculated by (42-37.8)/8= 0.525 or half grain steps) 37.8 38.3 38.8 39.3 39.8 40.3 40.8 41.3 41.8 That gives me a starting load a little over Sierra's start point but at the start point from the QL output (so I guess über safe) and a finishing point 2.5 grains under Viht's and Lee's max charge, also at the upper end of the QL scale of safe loads. It's utterly weird, but not surprising, that yet again Viht's web data seem to conflict with everything else (except Lee) and way over the safe level from the QL output. Viht's published data seems much more in line with Sierra and QL. What thinks you lot? *Good practice Edited February 20, 2015 by mick miller Quote Link to comment Share on other sites More sharing options...
neutron619 Posted February 20, 2015 Report Share Posted February 20, 2015 (edited) Well I'll reply to you more later when I've had a think, but my first observation is that the Lee manual takes a lot of it's data direct from other manufacturers websites, which probably explains why their numbers match what's online for the Viht data. Their numbers also tend to be on the hot side compared to the other publishers, in my very limited experience. The Sierra numbers are typically cool - again, that matches up with my limited experience. My other observation at this point is that it is strange that you seem to be struggling to get to the maximum loads of any published data. From what I've read and experienced myself, that's usually indicative of something wrong with the loading process rather than that one can't reach the top number in a given rifle. Loading data, hotter or cooler, is necessarily conservative because it has to work in battered, 100-year old rifles as well as strong modern actions. In most cases, one should expect to get to the published maximum, which makes me wonder whether something is amiss... Edited February 20, 2015 by neutron619 Quote Link to comment Share on other sites More sharing options...
neutron619 Posted February 20, 2015 Report Share Posted February 20, 2015 (edited) Ok - one more quick observation for you, but then I have to go and do some work! Looking at the QL data, the "amount of propellant burnt" column is pretty telling. The whole range of charges is saying that all the powder has been burnt, which suggests that N140 is a powder that is somewhat too fast for the load you're trying to construct. Now I'll just take a time out here and say that this confuses me as well. We've started looking at powders which, though appropriate to .243 Win in many peoples' experience, seemed to be too slow for the rifle - remember the poor obturation / case expansion and relatively low velocities you saw with IMR 4350? Now you've moved to a slightly faster powder and it looks like you're going to see dangerous pressure before you reach a reasonable velocity / maximum charge for the round. Every rifle is of course different, but to me, this seems a bit fishy. I'm struggling to rationalize what you're seeing here. Going back to the "propellant burnt" question, what you would ideally hope for (or what I'd hope for at least) is a load which burns completely, but progressively, such that combustion finishes whilst the bullet is still in the barrel, but close to exiting the muzzle. When this happens, you're not allowing the bullet to experience friction against the barrel without being actively driven, so it's not at risk of slowing down before it exits, but at the same time, you're not wasting propellant and increasing noise / recoil by burning it after the bullet has exited the muzzle. Obviously the QL data you posted doesn't tell us whether combustion finishes 6" into the barrel or 0.1" before the muzzle, but it might be worth a thought. Beyond that, I'm still not sure. .243 has always been a bit borderline as far as reaching the 1700ftlbs level required for deer, but I would expect most modern rifles with any kind of maximum load to be approaching 1900-2000ftlbs energy. This is another way of saying that it feels like something strange is going on. I'm going to go home and have a play with QL and see if it gives me any more insights. In the meantime, hopefully one of the experts can come along and help us both understand what's going on... :-S Edited February 20, 2015 by neutron619 Quote Link to comment Share on other sites More sharing options...
mick miller Posted February 20, 2015 Author Report Share Posted February 20, 2015 I was supplied the QL data from another forum, not sure if everything is okay with it to be honest. I was more interested to see if the proposed test charges would be okay - the starting load and maximum? I'm loathe to go and load at the Lee/ Viht maximum as I guess this would be well over pressure. I chose N140 as so many other people had recommended it over the N150, it being just above Varget in the burn rate charts. Nosler gives data for Varget and a 70gn starting at 38gns and going up to 42gns (close to what my research tell me to try), I know you cannot substitute one powders data for another, which isn't what I've done here. But they look pretty close on paper. It's also the most accurate load that Nosler tried with that rifle/ bullet combo. Quote Link to comment Share on other sites More sharing options...
mick miller Posted February 20, 2015 Author Report Share Posted February 20, 2015 (edited) From what I've read and experienced myself, that's usually indicative of something wrong with the loading process Well, I struggle to see what, if anything, is going wrong with that. Cases wet tumbled and spotless. FL resized, cleaned and sizes spot checked Trimmed to SAAMI spec. Primed CCI Large Rifle Primer. Powder measured using RCBS 505 scales and I'm anal about getting that right. Bullet seated to Nosler specs for that bullet type and weight. Seating depth checked on every one with Hornady tool so its measured to ogive not tip. Edited February 20, 2015 by mick miller Quote Link to comment Share on other sites More sharing options...
mick miller Posted February 20, 2015 Author Report Share Posted February 20, 2015 Maybe my rifle's a duffer? Quote Link to comment Share on other sites More sharing options...
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