Wildcat69 Posted July 7, 2013 Report Share Posted July 7, 2013 Hi everyone, just got my ftr rifle the other day and I have yesterday broke in the barrel with the 10x 1 shot cleaning followed 1x shots cleaning and last with 5 shots cleaning method. I could see improvement in foulling with less then 3-5 patches ( the joy of a good match barrel ). The barrels is a trueflite 32" f class contour in 1-10" twist. For plincking and < 600 yards shooting I have sierra Palma 2156 155gr and for long distance 185gr hybrids. I used for breaking in the sierras and found with a light load of 42.5gr of N140 to show ejectors marks already. I know most ftr boys shoot 155gr with around 46gr, would the fast twist build up more pressure then a slower one? Bullets are seated well off the lands as it is chambered for the heavier 185gr-200gr bullets. I didn't chrono cause I lost one of the bars holding reflector strip. I am aware of spin drift and it's not ideal to shoot 155gr out of this barrel but for what they cost compare to Bergers. I'll try to make something wich hold the strip as I want to do some load development today. Cheers By the way it shoots freaking great!!! Thanks John from Dcr. Link to comment Share on other sites More sharing options...
Laurie Posted July 7, 2013 Report Share Posted July 7, 2013 The simple answer is 'yes in theory', but it shouldn't make enough difference for you to notice in practice. You certainly should NOT be getting over-pressure signs with 42.5gn N140 and Sierra 155s in a long-throat chamber. You can get much higher pressures in your first few running-in rounds sometimes until the tool-marks are smoothed out and some barrels can be a bit tight for the first few tens of shots .... but even so ?! Are you sure they're pressure induced ejector recess extrusion? What make of case, too? Incidentally, today's match bullet quality is so good, there is no precision loss from shooting 155s through a quality 1 in 10-inch twist barrel. Many F/TR league shooters do this these days. Link to comment Share on other sites More sharing options...
Lukas_K Posted July 7, 2013 Report Share Posted July 7, 2013 Only a random thought - you sure you cleaned perfectly to dry bore on the range? Just realized - you say ejector marks, have you meant the extractor? For ejector marks, I´d run a few empty cases through the rifle at home, may by there´s only excessive spring power hitting them out too hard. Link to comment Share on other sites More sharing options...
Wildcat69 Posted July 7, 2013 Author Report Share Posted July 7, 2013 Just came back to do some load development! I may need to bin my chrony as it has given the most strangest figures. It all started all fine until half way around my loads and had spikes around the 3000fps with 44.5gr loads. This is not the first time it happened to me! The brass is new Lapua, they are all turned and have all equal length. The powder double weighed and trickled at the end. https://dl.dropboxusercontent.com/u/100609622/IMG_0309.jpg https://dl.dropboxusercontent.com/u/100609622/IMG_0308.jpg I have cleaned yesterday when I was doing breaking in but I always leave it dry. See what you think. Cheers Link to comment Share on other sites More sharing options...
Andrew Posted July 7, 2013 Report Share Posted July 7, 2013 You can get much higher pressures in your first few running-in rounds sometimes until the tool-marks are smoothed out and some barrels can be a bit tight for the first few tens of shots .... but even so ?! Much higher pressures?? Really? ~Andrew Link to comment Share on other sites More sharing options...
Laurie Posted July 7, 2013 Report Share Posted July 7, 2013 Yes, really! Copper fouling increases resistance to bullet travel, and if the first running-in rounds see a lot of copper taken off the bullet, it's quite common to get higher pressure signals from those rounds. Think about it. If the first round or three sees very heavy coppering that takes a couple of soakings and brushings of a decoppering agent to dissolve the fouling, so how did that copper get all the way down the bore - usually clearly visible at the muzzle end. The degree of resistance to the bullet travelling through the throat is such that it not only removes a fair slice of copper from the bullet, but received wisdom says that some of it is melted such are the temperatures and pressures generated by the process, so it follows the bullet down the barrel in the powder gasses to condense at the muzzle end as temperatures drop. Look through a borescope in this situation and you see a heavy deposit just ahead of the chamber, then another running a couple of inches in from the muzzle. You don't remove metal off the bullet without increasing pressures. Leave the fouling in the barrel and that increases pressures too for subsequent shots. However, the degree this occurs depends on the barrel and the newly cut throat and the degree of coppering varies enormously from chamber / barrel to chamber / barrel. It's also, as you'd expect, usually much more pronounced on the first round through the barrel as it's doing the greatest amount of work in running the throat in. I'm talking stainless match barrels and gunsmith cut chambers - factory rifles don't usually exhibit much difference on a new barrel so far as I've ever seen. Nevertheless, unless it was a hot load, I'd still not expect to see ejector marks appear, and this was not in any way a hot load. Looking at the image of the case-heads now posted, there are slight through clear ejector marks on maybe a quarter of the case-heads. But, primers remain rounded with a deep firing pin impression that whose outside edges also remain rounded, all classic signs of light to moderate pressures. Some primers, presumably from the heavier loads are starting to flatten across the back edge of the cup and show a sharper edge to the firing pin indentation, but their outside edges retain a gentle radius, so this suggests 'standard' rather than heavy pressures. I know primer condition can mislead in various ways, but you'd nearly always see at least some heavy pressure signs on them at the point where ejector marks appear. Wildcat69, are you jumping or jamming the bullets? Any other pressure symptoms such as initial resistance to bolt lift? Decap the cases with the heaviest marks and see if the primers are ejected easily, or take usual pressures to punch them out. Link to comment Share on other sites More sharing options...
Andrew Posted July 7, 2013 Report Share Posted July 7, 2013 Interesting. I've only run two completely virginal barrels in a pressure gun and we didn't pay attention to the data. I don't remember anything extra ordinary but it may have happened. I was too busy focusing on other issues relating to set-up and calibration.~Andrew Link to comment Share on other sites More sharing options...
DaveT Posted July 7, 2013 Report Share Posted July 7, 2013 Its not likely ..... but is there any chance that the brass is too long and crimping the bullets or the reamer was for a tight neck? Link to comment Share on other sites More sharing options...
Wildcat69 Posted July 7, 2013 Author Report Share Posted July 7, 2013 Looking at the image of the case-heads now posted, there are slight through clear ejector marks on maybe a quarter of the case-heads. But, primers remain rounded with a deep firing pin impression that whose outside edges also remain rounded, all classic signs of light to moderate pressures. Some primers, presumably from the heavier loads are starting to flatten across the back edge of the cup and show a sharper edge to the firing pin indentation, but their outside edges retain a gentle radius, so this suggests 'standard' rather than heavy pressures. I know primer condition can mislead in various ways, but you'd nearly always see at least some heavy pressure signs on them at the point where ejector marks appear. Wildcat69, are you jumping or jamming the bullets? Any other pressure symptoms such as initial resistance to bolt lift? Decap the cases with the heaviest marks and see if the primers are ejected easily, or take usual pressures to punch them out. Yea only have taken a pic of the first 20 ish from 33 and showed primer signs exactly as you explained but you can't see very well but all of them have the ejector mark. The bullets are jumped well off the lands and I have so far no heavy bolt release even with the hottest load at 46.9gr. But to be honest it wasn't the most accurate load so I am happy with that. So far the best groups came in between 45.5 and 46.3gr, so will have to continue and get the best out of it. What do you think of the velocity? Don't you think there something strange with the reading of the fps? I am glad you think it's ok with the pressure, this is my first match rifle so want to make sure it's all good. Thanks for the input Laurie, much appreciated again. Link to comment Share on other sites More sharing options...
onehole Posted July 8, 2013 Report Share Posted July 8, 2013 Just came back to do some load development! I may need to bin my chrony as it has given the most strangest figures. It all started all fine until half way around my loads and had spikes around the 3000fps with 44.5gr loads. This is not the first time it happened to me! The brass is new Lapua, they are all turned and have all equal length. The powder double weighed and trickled at the end. https://dl.dropboxusercontent.com/u/100609622/IMG_0309.jpg https://dl.dropboxusercontent.com/u/100609622/IMG_0308.jpg I have cleaned yesterday when I was doing breaking in but I always leave it dry. See what you think. Cheers Will bring my chrony on Wed mate and check out a few things with you,,,cheers D Link to comment Share on other sites More sharing options...
The Gun Pimp Posted July 8, 2013 Report Share Posted July 8, 2013 Hi everyone, just got my ftr rifle the other day and I have yesterday broke in the barrel with the 10x 1 shot cleaning followed 1x shots cleaning and last with 5 shots cleaning method. I could see improvement in foulling with less then 3-5 patches ( the joy of a good match barrel ). The barrels is a trueflite 32" f class contour in 1-10" twist. For plincking and < 600 yards shooting I have sierra Palma 2156 155gr and for long distance 185gr hybrids. I used for breaking in the sierras and found with a light load of 42.5gr of N140 to show ejectors marks already. I know most ftr boys shoot 155gr with around 46gr, would the fast twist build up more pressure then a slower one? Bullets are seated well off the lands as it is chambered for the heavier 185gr-200gr bullets. I didn't chrono cause I lost one of the bars holding reflector strip. I am aware of spin drift and it's not ideal to shoot 155gr out of this barrel but for what they cost compare to Bergers. I'll try to make something wich hold the strip as I want to do some load development today. Cheers By the way it shoots freaking great!!! Thanks John from Dcr. Wildcat, Your load of 42.5 is TOO LOW - you are getting marking from the ejector-pin hole because the case isn't obturating and gripping the chamber wall - all the load is transferred to the boltface. Link to comment Share on other sites More sharing options...
Wildcat69 Posted July 8, 2013 Author Report Share Posted July 8, 2013 Wildcat, Your load of 42.5 is TOO LOW - you are getting marking from the ejector-pin hole because the case isn't obturating and gripping the chamber wall - all the load is transferred to the boltface. Well we learn something new everyday. Thanks for the tip, so far load wise I am between 45- 46.5gr of N140. So it's getting there! Link to comment Share on other sites More sharing options...
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