dadioles Posted June 19, 2014 Report Share Posted June 19, 2014 (edited) Following on from comments elsewhere about Hornady 17gr HMR V-Max variance...... My experience is that there is little variation between bullets and batches or tip colour or whether the case neck is cracked or not. I just tried a quick test at 50 yards with the F1 Chrony placed about 1 foot in front of the muzzle. All bullets landed easily within the area of a pound coin, no fliers. The dense stack of magazines that I used as a back stop was penetrated to a depth of five inches. Bullets were fragmented and magazines turned to dust around the bullet holes, quite devastating. Rifle was Anschutz 1517 with 14" barrel and DM80 moderator. Normal bullets bright red tips: (fps) 2469 2433 2459 2442 2412 2459 2445 ave - 2446 Normal bullets dark red/brown tips: 2533 2378 2434 2467 ave - 2453 Bullets with cracked necks prior to firing: 2573 2587 2671 2606 2691 2609 2459 ave - 2599 The fact that they all shot the same is what matters. It is interesting that the ones with cracked cases almost all flew faster (average 140fps faster - nearly 6% ) . The difference in impact point would probably show better at 100 yards, a job for another day. I have another 30 or so with cracked necks that I can test. All my bullets are stored in warm dry conditions. I expected the bullets with cracked necks to fly slower, not quicker. Maybe other shooters have damp ammunition. One way of looking at it is that bullets with cracked necks are a premium product - they fly faster!! Edited June 19, 2014 by dadioles Quote Link to comment Share on other sites More sharing options...
the enigma Posted June 19, 2014 Report Share Posted June 19, 2014 Good post. That show's up quite a spread, between high and low, in fps, though I doubt a rabbit would notice the difference. I never felt that cracked cases had any major effect on accuracy, when I miss, it more likely to be my fault rather than the case. Quote Link to comment Share on other sites More sharing options...
Blunderbust Posted June 19, 2014 Report Share Posted June 19, 2014 You are a brave man knowingly shooting rounds with cracked necks. I agree with what you say about the damp ammo, but since I have removed all the cracked rounds from my batch, I have never had a single problem with my HMR. Quote Link to comment Share on other sites More sharing options...
activeviii Posted June 19, 2014 Report Share Posted June 19, 2014 Glad you notice the split gave more. We put a friends once the f1 last week and notice the same. Hornady rounds ran average 2430 but the ones with splits gave 100+ more. The splits where on the shoulder, not on the neck. Quote Link to comment Share on other sites More sharing options...
cooter Posted June 20, 2014 Report Share Posted June 20, 2014 Does the crack mean that there is propellant in the case? Could be worth weighing a few and see what the difference is. Quote Link to comment Share on other sites More sharing options...
dadioles Posted June 20, 2014 Author Report Share Posted June 20, 2014 (edited) Glad you notice the split gave more. We put a friends once the f1 last week and notice the same. Hornady rounds ran average 2430 but the ones with splits gave 100+ more. The splits where on the shoulder, not on the neck. All of my cracked bullets show the split from the neck (where the bullet is inserted into the brass) to the shoulder. In this photo you can see the crack in the neck of the new ammunition. It does extend to the shoulder but is too fine to see in the photo. After firing, the crack has opened up significantly, as you would expect, and more clearly defined by powder burn. The main outside body of the cartridge is 'dirtier' but whether this is discolouration caused by the heat of combustion or the smear of smoke deposit I am not sure. The bullets fire perfectly well and I do not have any issue with them, cracked or not cracked. Apparently several million of these bullets are sold in the UK alone each year, the failure rate is tiny. I cannot help thinking that in the majority of cases where users have problems, it is down to the user. Was the ammunition allowed to get damp? Is the rifle barrel, chamber and action cleaned regularly and properly? Edited June 20, 2014 by dadioles Quote Link to comment Share on other sites More sharing options...
dadioles Posted June 20, 2014 Author Report Share Posted June 20, 2014 Does the crack mean that there is propellant in the case? Could be worth weighing a few and see what the difference is. Ok, just weighed 10 with cracks and 10 without cracks. I used a laboratory analytical chain balance (just happen to have one around ) There was no meaningful difference between the two. They were VERY consistent - all credit to Hornady. Averaged over 10 bullets: Cracked cases = 40.351 grains Normal cases = 40.402 grains I am still at a loss to understand why bullets with cracked cases fly faster than those that do not. The only thing I can think of is that the bullet head is gripped less tightly when the neck is cracked and is therefore released more easily. Another possibility is that cracked cases are harder and flex less, thereby accepting greater case pressure. Hold on a minute..... another pig just flew by.... I think it was clutching a straw...... Must get a life...... Quote Link to comment Share on other sites More sharing options...
Wurzle Posted June 20, 2014 Report Share Posted June 20, 2014 If the neck tension is lower ,then the pressure will not build up as high. Also the split case won't seal properly in the chamber. So lower pressure is the result here, too. So why do they exit the muzzle faster? Funny old thing. Quote Link to comment Share on other sites More sharing options...
boo Posted June 20, 2014 Report Share Posted June 20, 2014 Out of curiosity, weigh each round, will have to do a fair few, see if any weight difference? say 2.4g to 2.7g? then weigh empty shells get an average for that, say roughly 1.1g, then take into consideration a 17grain tip = 15.5grain to 1 gram , work out the math and see if there is a powder difference in each load! Looking into split necks apparently its due to the annealing process once the primer is inserted into the shell then necked down. As to the gun or operator for jams, had 2 shells that wouldn't come out,had to rod them, each split was 8-10mm long! So lastly more is not always best when accuracy is concerned,and what a certain barrel likes.Love the hmr but aafter testing nearly 800 rounds of Hornady ammo found which weight shoots the best,but should factory ammo have such varancies? Quote Link to comment Share on other sites More sharing options...
Blunderbust Posted June 21, 2014 Report Share Posted June 21, 2014 Out of curiosity, weigh each round, will have to do a fair few, see if any weight difference? say 2.4g to 2.7g? then weigh empty shells get an average for that, say roughly 1.1g, then take into consideration a 17grain tip = 15.5grain to 1 gram , work out the math and see if there is a powder difference in each load! Looking into split necks apparently its due to the annealing process once the primer is inserted into the shell then necked down. As to the gun or operator for jams, had 2 shells that wouldn't come out,had to rod them, each split was 8-10mm long! So lastly more is not always best when accuracy is concerned,and what a certain barrel likes.Love the hmr but aafter testing nearly 800 rounds of Hornady ammo found which weight shoots the best,but should factory ammo have such varancies? I think it is unacceptable that we have so much problems with the ammo never mind variations in the weight. I have to admit that my problems were all with the blue tips (Hornady) and after filtering them and removing numerous split cases (cant remember how much exactly) I have never had a problem. I am now about to change my CZ for an Anschutz and will not buy the blue tips again, but will very carefully scrutinise my next batch of rounds, results to follow. I have to admit though I will not be knowingly feeding my rifle sub standard rounds. Quote Link to comment Share on other sites More sharing options...
dadioles Posted June 21, 2014 Author Report Share Posted June 21, 2014 I think it is unacceptable that we have so much problems with the ammo never mind variations in the weight. I have to admit that my problems were all with the blue tips (Hornady) and after filtering them and removing numerous split cases (cant remember how much exactly) I have never had a problem. I am now about to change my CZ for an Anschutz and will not buy the blue tips again, but will very carefully scrutinise my next batch of rounds, results to follow. I have to admit though I will not be knowingly feeding my rifle sub standard rounds. When blue tips came out they were sold cheaper than red tips. There were many conspiracy theories. Frankly, I found the blue tips to be identical to red tips apart from the colour. I emailed Hornady at the time (2011) and was given a very simple explanation.... They had stocks of blue polymer "... for FN for the 5.7X28 round ..." and were short on stock of the red. All the bullet heads were manufactured identically but blue ones were sold at a reduced price. As simple as that. It is very easy to blame the ammunition... Every week I read in these forums about people who never clean their rifles 'until the accuracy goes off' and then it is a quick run through with a bore snake. Quote Link to comment Share on other sites More sharing options...
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