Printable View
hey guys i am trying to figure out at what depth my bullet is hitting the lands and from what im getting, im on the lands at 2.615, i want to be .10 off the lands so that brings me to 2.605 ish. does this sound right? the hornady book and many others call for col at 2.640. im using the fired case and bullet method and im getting consistant results at about 2.614-2.616. someone please help me out. i dont know if this helps but its a 9.25 twist and im using sierra 85gr. hpbt.
If you have a Lee collet die you can make a light necked sized case for a COAL gage. Just enough tension to set the bullet and pull it out, or get a Hornady COAL gage.
As far as the what bullet to use for your rifle.... use this site... http://kwk.us/twist.html
flatshooter im doing the bullet gauge deal already and im getting results but i want someone to confirm that my findings sound about right or something on that line, or someone flat out tell me im doing somthing wrong and my results dont sound right.
I can certainly understand your desire to as "perfect" as possible, but what are you trying to accomplish? How is the accuracy in the rifle? Is there a condition you trying to fix or correct? I have a number of Savage rifles that shoot less than 1" with 3 shots, and one that shoots 1/2" with 5. However, these are all hunting rifles. Just my thoughts. Typically, I get enough accuracy for hunting use by trimming cases, playing with powder charges, different type or weight of bullet, etc. You can always try a set of competition dies, but you may not see much gain from a stock rifle. Just my opinion.
yes i understand what you are saying an to say the least my gun shoots very well for the average hunter. id say it shoots 3 shots at about 1.25 inches at 100. i shoot woodchucks out at around 300 and want to know that were im aiming is were im hitting, you know?
what are you seating your bullets at?
once you determine the COAL then you also need a bullet comparator by sinclair. Whatever the bullet is touching the lands and back off .010 etc.... and shoot it. Doesn't matter what we set our cartridges at, it only matters, for your rifle, what your cartridges are set at.
GS, I've had the same concern. Anytime I deviate that much from reliable source, I want to be sure that I've got it right. The Hornady guage is not foolproof (in my opinion). sometimes the case is not fully seated in the chamber. Even once-fired cases sometimes have a little 'spring back' although this usually gives a longer col. The guage doesn't seat the case like the bolt does.
If I understand you correctly, if you simply loaded to the recommended col, the bullet would be jammed into the rifling?
Are you sure you're using the exact same bullet as the one referenced in the manual?
Have you tried seating a bullet (a dummy round) at the recommended col to see if there are rifling marks on it? I use a sharpie marker to color the bullet. That should give you more confidence in your set up.
i use the sierra bthp 85 gr. i also looked in the sierra book i have and the col is still 2.640. i got my question answered already by just sitting and thinking but i guess i just want to know is 2.640 the max length or the minimum. i am getting 2.615 with the dummy rounds, can that be?
Using this method with my steven 200 in 243 and 70gr SMKs:
http://www.youtube.com/watch?v=kaA3G...yer_embedded#!
I got the following results:
1st try: 2.684
2nd try: 2.684
3rd try: 2.687
4th try: 2.685
I have been loading to a COL of 2.67 +/- .002. I have found that the tips (Meplat?) on the SMKs are no perfectly flat and will yield a little variation. This is where using a comparator to measure the ogive would help.. planning to pick up the hornady set eventually.
If you are using a fired case without partially sizing the neck then I suspect there is not enough tension on the neck to get an accurate read. Your results sound short to me.
I'm still pretty new at this so take what I say with a grain of salt :)
well thats the thing because they sound short to me also but that is the reading im consistantly getting. man i need the right tools!
Don't get to hung up on book COL. It is an average length for an average chamber. It sounds like the throat of your chamber is a little short. No biggy! I would rather have a short throat than one that is to long to get the bullet near the lands.
Besides, keep shooting that 243 and your COL will grow as the throat erodes.
ya even after all the replies i checked it agian and i am getting 2.615 so i will just assume thats gotta be it and shoot.