rubyred Posted March 6, 2015 Report Share Posted March 6, 2015 (edited) Hi I am quite new to this reloading. I have been using 55 grain vmax some body said try 50 grain serria blitzking.I have all the stuff hornday lock load the ogive on the v Max is 1.934 with the dummy bullet and 55 grain head but when I checked the 50 grain the ogive is 1.958 with dummy bullet and 50grain head.can somebody please explain.I AM NOT CHECKING THE FULL LENGTH OF THE BULLET BUT THE OGIVE.thank you all Edited March 6, 2015 by rubyred Quote Link to comment Share on other sites More sharing options...
seeker Posted March 6, 2015 Report Share Posted March 6, 2015 (edited) This articles a bit wordy but explains it well .. http://www.bergerbullets.com/effects-of-cartridge-over-all-length-coal-and-cartridge-base-to-ogive-cbto-part-1/ http://www.bergerbullets.com/effects-of-cartridge-over-all-length-coal-and-cartridge-base-to-ogive-cbto-part-2/ There are variations between bullets Edited March 6, 2015 by seeker Quote Link to comment Share on other sites More sharing options...
rubyred Posted March 6, 2015 Author Report Share Posted March 6, 2015 Hi have seen that before.what I am trying to get at the dia of the two bullets are identical why is the ogive on the two rounds different from the base of the case. Quote Link to comment Share on other sites More sharing options...
old man Posted March 6, 2015 Report Share Posted March 6, 2015 With the greatest of respect stop now until you do understand! You need to have read and understood the contents of at least 1 reloading manual or have a mentor to ensure your own and the safety of others! Quote Link to comment Share on other sites More sharing options...
rubyred Posted March 6, 2015 Author Report Share Posted March 6, 2015 What I am trying to get at if both bullet heads are same dia why is it that they are giving different ogives from same base of one brass case. Quote Link to comment Share on other sites More sharing options...
wymberley Posted March 6, 2015 Report Share Posted March 6, 2015 For exactly the same reason that a Ford is different to a Nissan which is different to a Honda. Quote Link to comment Share on other sites More sharing options...
Bewsher500 Posted March 6, 2015 Report Share Posted March 6, 2015 secant and tangential ogives but in simple terms stop the mental masturbation and load the bloody things No rifle requires land kissing ogives to be accurate use it as a reference point for repeatablibilty rather than comparison of chamber to cartridge load with bullet seated a full calibre depth of shank (the flat side of the bullet not including ogive curve or boat tail) work up slowly from around minimum find a sweet spot tweak OAL either side if it fits in the mag, shows no pressure signs and shoots well you have passed the test! go shoot stuff you can make this as difficult or as easy as you want its not rocket science and does not require a PhD or a white coat people have been loading with scoops and mallets for donkeys years! Quote Link to comment Share on other sites More sharing options...
old man Posted March 7, 2015 Report Share Posted March 7, 2015 (edited) secant and tangential ogives but in simple terms stop the mental masturbation and load the bloody things No rifle requires land kissing ogives to be accurate use it as a reference point for repeatablibilty rather than comparison of chamber to cartridge load with bullet seated a full calibre depth of shank (the flat side of the bullet not including ogive curve or boat tail) work up slowly from around minimum find a sweet spot tweak OAL either side if it fits in the mag, shows no pressure signs and shoots well you have passed the test! go shoot stuff you can make this as difficult or as easy as you want its not rocket science and does not require a PhD or a white coat people have been loading with scoops and mallets for donkeys years! I agree Ed but surely not if you don't know which scoop, what a full calibre depth is or the distance to the lands etc? We all started somewhere but hopefully at a safe point? Edited March 7, 2015 by old man Quote Link to comment Share on other sites More sharing options...
snow white Posted March 7, 2015 Report Share Posted March 7, 2015 Hi old man if you read it he does know the distance to the lands what I am making out of it.it seams that the two types of bullet head are giving different readings to the ogive on the bullet. Quote Link to comment Share on other sites More sharing options...
zx10mike Posted March 7, 2015 Report Share Posted March 7, 2015 different shape bullets will have different ogive measurements and different bearing surfaces .as long as you treat each bullet as a new load from scratch and work carefully this should be no problem.find the distance they jump 10 tho is a good place to start if they will mag feed or just load to mag length. enjoy and work carefully. Quote Link to comment Share on other sites More sharing options...
Dougy Posted March 7, 2015 Report Share Posted March 7, 2015 Rubyred, bewsher is on tbe button there regards to loading, don't over complicate things it will only spoil things. Quote Link to comment Share on other sites More sharing options...
rubyred Posted March 7, 2015 Author Report Share Posted March 7, 2015 It is that that a taper is a taper wether but where the taper starts it should still be the same.if you have a tube and you put two different tapered rods in it so long as they are the same dia they will touch/ogive in the same place.so why are the lengths over the two made up rounds different.thanks for looking Quote Link to comment Share on other sites More sharing options...
Dougy Posted March 7, 2015 Report Share Posted March 7, 2015 I think I understood, I think your referring to the the tool used for measuring the ogive, ? Try measuring the ID of the ogive using the comparator, then the barrel, they will be different. Quote Link to comment Share on other sites More sharing options...
Underdog Posted March 7, 2015 Report Share Posted March 7, 2015 Oh boy, so stressful, makes me wonder how I ever managed! Quote Link to comment Share on other sites More sharing options...
seeker Posted March 8, 2015 Report Share Posted March 8, 2015 (edited) The diameter of the hole in the gauge / comparator doesnt change. The point of contact with the bullet will always be where the bullet diameter matches the gauge....so your comment on taper is right.(?) The distance you are interested in is from the base of the case to where the gauge meets the bullet after it is seated = CBTO. Adjust the seater up or down so the CBTO becomes the same for both bullets. But the OAL from base to tip varies between bullet types and even bullets from the same batch because of manufacturing ""tolerances"". One possibility is that because the bullets are different shapes the bit in the seater die is pushing on the very tip of the bullet rather than slightly down the ogive and causingthe variation.? Which seating die are you using? If you want to see the contact point then mark the bullet with a felt tip. As said 'dont complicate things' but sometimes wot yoda says on the tin is not wot it does not do. Edited March 8, 2015 by seeker Quote Link to comment Share on other sites More sharing options...
rubyred Posted March 8, 2015 Author Report Share Posted March 8, 2015 Hi am using honrdy lock load gear with bullet that screws on the rod and copmarator with dial callipers.the two heads are 50grain serrai bliztking and 55grain vmax.the difference between the two marks using felt pen is 25 thou the serrai sticks out further so not a lot of head in case.I am not trying to make it completed but it is annoying which I had not brought serrai heads will go back to vmax.all this came about over a conversion in gun shop I was going to go heavy but some bright spark said go lighter get a flater round.stopping with vmax end of story thanks for all the conversion on subject.rubyred Quote Link to comment Share on other sites More sharing options...
seeker Posted March 8, 2015 Report Share Posted March 8, 2015 Excellent result! If you're getting a consistent 0.025" between the bullets you're doing something right... The different shapes and angles of the bullet ogives may first touch on the short TAPER on the start of the rifling at a different point. Its probably why the precision bench rest people specify that the throat and leade of the chamber be cut to match one particular bullet .. made to measure v off the rack? 1 size exactly fits 1 shape .. and another shape is 25thou out? Quote Link to comment Share on other sites More sharing options...
Bewsher500 Posted March 10, 2015 Report Share Posted March 10, 2015 have you actually shot any of them? I am still not sure what you are describing as the difference in OAL and why it is an issue These 5 bullets pictured below are all seated with the ogive on the lands (reference dummy bullets) the centre three in theory should be the same OAL, note that OAL is NOT measured to the Ogive. It is OVER ALL LENGTH the change in curve design on the outer surface of the bullet, the ogive, means that your reference point using the comparator will, can and is always in a different location on each different bullet design...and even between the same design. Note the Scierra SMK's in the centre are all the same theoretical Ogive curve, but they are different weights and they all have slightly differing OAL's (which is not tip related) does that make sense? As to loading using the lands I seriously doubt you will need to demonstrate the accuracy of bullet seating you describe to get acceptable groups. I know where my lands are, but only in relation to the bullet I am using (see above reference rounds) The measurement in inches is actually irrelevant. What seating die are you using? bet you it has some run out when seating. They all do By using a dummy round and the actual case and bullet you are loading (rather than a Hornady modifed case and bullet combo) you are removing all stages of error in the measurement Use a fired case, crimp the mouth slightly so the bullet is a fairly tight push fit, slightly lube the ogive chamber, measure, chamber, measure, chamber, measure, chamber measure, chamber, measure, (repeat for as often as you like), take an average of the measurements and you have an ACTUAL OAL for that bullet and case in your rifle. my comment on calibre depth is related to starting point for load development either Do a ladder test or choose a powder range (20-25gr for example) choose an increment value (0.2gr or 0.5gr for example) load groups of rounds at each charge level seat the bullet at least a full calibre depth (you are shooting .224/5.56 right, then seat the bullet so that 5.5mm of the flat bearing surface is in the neck. shoot groups find the sweet spot(s) usually two at upper and lower ranges depending on how wide your charge range is fine tune this charge level first for smaller increments of powder either side THEN for depth either side of starting point You should see an obvious correlation between changes and group size you will see at no point do you actually need to know the distance to the lands or have an actual reading on OAL until the end its just as easy to keep a dummy reference round for each load I do that to cross reference any seater die settings for each one hope that helps Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.