Good day fine people of CGN. I am trying to work out a load from the Lyman 49th Edition reloading hand book for the 308. I can not find any info for the Hornady 178gr Match BTHP for load data. The only info I have found was on the 178 grain AMAX and another for a 175gr BTHP. Would it be safe to say that I could load the Hornady 178gr Match BTHP to the same parameters as the AMAX ? Between the 175gr BTHP recipe and the 178gr AMAX their suggested starting grains and max are almost identical the only thing different is OAL. I have reloaded lots for pistol but this is my first attempt at reloading for rifle. Any suggestions would be greatly appreciated.
Hornady 178g Match BTHP - IMR 4064
- Thread starter 75-B
- Start date
All three bullets you mention are copper jacketed bullets with lead cores; one of them also has a plastic tip. They are interchangeable in terms of load data.
The rifle can't tell a 175gr from a 178gr so there's no real difference there.
Assuming you are starting at the start load and working up, you're fine. The start loads in most manuals are quite tame and a good deal below the max rated pressure for a cartridge. Pressures of course vary from case to case based on a plethora of differences (chamber, throat, barrel, brass, powder lot, etc.) so there is always a healthy safety margin because of the publishers lawyers. I never look for data specific to my brand of bullet and rarely ever do use data that specific; only when it's a coincidence that what I have matches the bullet I'm using. Load for the weight (+/- 2-3%) and type (solid copper, frangible, copper jacket with lead core, etc.) and you'll be fine.
OAL is something else that isn't written in stone (unless you're NATO). I load the bullets to the cannalure (crimp groove) if there is one but most of the time I just load the bullets as far out as possible but short enough so they still cycle properly in the action. If I want to jam the bullet into the rifling and don't mind single-feeding the rounds in the rifle I'll load to the rifles max COAL for that bullet. There are various ways to measure this but it comes with other considerations. If you're just starting it's best to keep it simple at first.
The rifle can't tell a 175gr from a 178gr so there's no real difference there.
Assuming you are starting at the start load and working up, you're fine. The start loads in most manuals are quite tame and a good deal below the max rated pressure for a cartridge. Pressures of course vary from case to case based on a plethora of differences (chamber, throat, barrel, brass, powder lot, etc.) so there is always a healthy safety margin because of the publishers lawyers. I never look for data specific to my brand of bullet and rarely ever do use data that specific; only when it's a coincidence that what I have matches the bullet I'm using. Load for the weight (+/- 2-3%) and type (solid copper, frangible, copper jacket with lead core, etc.) and you'll be fine.
OAL is something else that isn't written in stone (unless you're NATO). I load the bullets to the cannalure (crimp groove) if there is one but most of the time I just load the bullets as far out as possible but short enough so they still cycle properly in the action. If I want to jam the bullet into the rifling and don't mind single-feeding the rounds in the rifle I'll load to the rifles max COAL for that bullet. There are various ways to measure this but it comes with other considerations. If you're just starting it's best to keep it simple at first.
Thank you so very much for the schooling on that Sir. I will have to read up on crimp grove. I was introduced to base to ogive the other day and I am still learniong that. I do not mind the idea of single-feeding because I plan on taking shots slow at first and recording data at various distances and environments until a proper data sheet is complete. Would you say that the jam method could possibly a little more accurate down range ? And is a good method for finding max COAL to load an unprimed empty brass with the bullet loose and as far out as possible . Then cycle action and see what your left with for OAL ?
Some bullets like to be jammed into the rifling (Berger VLD's come to mind) while others prefer to be anywhere from .010" to .050" from the lands for optimum accuracy. It's a trial and error process. Personally I just go anywhere from .010" to .020" from the lands and that's good enough for my mediocre skills to shoot groups I like (occasionally under 1/2 MoA but usually around 1/2 to 3/4 MoA). That's if your chasing the smallest groups possible. If you're just after reasonable accuracy (3/4 to 1 MoA) then whatever the longest that will fit in your magazine works well.
One way is to colour a bullet with a Sharpie and chamber it in a partially sized case so it scratches the ink off the bullet. This way even if the bullet sticks in the rifling and the case ejects without it you can still check your measurement. There are also tools available that use modified cases to measure these things more easily; Hornady makes a very good one.
Personally I use a method I read here on CGN. You take a plastic or hard wood dowel of roughly bore diameter and drop it down the bore with a closed bolt and empty chamber. Carefully scribe a mark with a knife at the end of the muzzle. Now put the desired bullet into the throat of the chamber, hold it in place with a plastic pen, wood dowel, or something else that wont damage the chamber. Now put the rod back down from the muzzle and scribe another line. Measure between these and you have a fairly close value (but not exceptionally precise). You can play with this COAL by adding or subtracting .010" or .015" at a time on your press and test chambering the rounds. A little marker on the ogive of the bullet will show you if you are hitting the lands or not. This method serves me well enough for my purposes. I'm not a competition shooter and just try to beat my own personal bests. I can't really compete seriously since I have a twitch in my trigger finger and wrist from focal dystonia.
One way is to colour a bullet with a Sharpie and chamber it in a partially sized case so it scratches the ink off the bullet. This way even if the bullet sticks in the rifling and the case ejects without it you can still check your measurement. There are also tools available that use modified cases to measure these things more easily; Hornady makes a very good one.
Personally I use a method I read here on CGN. You take a plastic or hard wood dowel of roughly bore diameter and drop it down the bore with a closed bolt and empty chamber. Carefully scribe a mark with a knife at the end of the muzzle. Now put the desired bullet into the throat of the chamber, hold it in place with a plastic pen, wood dowel, or something else that wont damage the chamber. Now put the rod back down from the muzzle and scribe another line. Measure between these and you have a fairly close value (but not exceptionally precise). You can play with this COAL by adding or subtracting .010" or .015" at a time on your press and test chambering the rounds. A little marker on the ogive of the bullet will show you if you are hitting the lands or not. This method serves me well enough for my purposes. I'm not a competition shooter and just try to beat my own personal bests. I can't really compete seriously since I have a twitch in my trigger finger and wrist from focal dystonia.
Wow that is some serious information. I think I have learned more in your last couple posts from you then I have in the last week online after work . I am defiantly going to run some experiments with those methods you speak of. Im not really into the competition side of it my self either. I just like going out and having fun. But I would like to get serious with making a precision load for my rifle and putting the data to paper. I really appreciate you giving me the time of day on this stuff your awesome.
I assume you are loading 308, not 30-06?
Measure you magazine length (if you plan on using it) and load a dummy round 25 shorter than that. That is the longest load you can make for the mag. Chamber it and see if it comes out with rifling marks. If no marks, use that as your starting OAL.
Try 38 to 43 gr in 0.5 gr increments. Load 5 of each and shoot for group. Watch for pressure signs.
Measure you magazine length (if you plan on using it) and load a dummy round 25 shorter than that. That is the longest load you can make for the mag. Chamber it and see if it comes out with rifling marks. If no marks, use that as your starting OAL.
Try 38 to 43 gr in 0.5 gr increments. Load 5 of each and shoot for group. Watch for pressure signs.
The slightest hint of difficult extraction in my rifle means 75,000 psi. Also watch for a shiny spot on the case head. Primers back out may mean low pressure. A blown primer looks quite different.
Do keep in mind that different brands of components will show different levels of pressure signs at different pressures.
-Federal primers tend to be very soft and will start to flatten in 30-30 loads which top out at 42,000psi. CCI primers just begin to flatten a tiny bit with an upper end 308 load which will be around 60,000psi. Other primers will show flattening at other pressures.
-Primer cratering (raised ridge around the firing pin dent) is often caused by oversized firing pin holes in the bolt face but can also be caused by a combination of too high a pressure and too soft a primer. In my experience CCI primers don't crater without an oversized hole even up to 65,000psi.
-Federal brass, likewise, can show ejector pin marks on the case head at a safe pressure for a cartridge like a 308 sometimes; definitely for something like a 270 win. Harder brass like military or Lapua wont show marks until pressure is dangerously high.
-Cases will start to stick in the chamber (stiff bolt lift, stiff extraction) at roughly the same pressure assuming it's the same rifle (different chambers will do it at different pressures) and the brass is of similar hardness in the neck/shoulder/body (the heads are significantly harder than those parts). Ganderites example of 75,000psi is in his rifle tells me he probably has a very smooth, polished chamber in the given rifle. I have a 308 with factory Remington chamber (tight but not polished) that gets a stiff bolt and sticky extractions only a little above max published velocities which probably means only a little above max rated pressure. Maybe 62,000-65,000psi? No way to tell for sure outside of a ballistic lab.
If you're looking to load to max it's best to use a chronograph and check for the max published velocity. It isn't a guarantee as there are still quite a few variables not taken into account but it's more reliable than looking at primers. For whatever reason I often find very accurate loads near the beginning to middle of load data in most modern rifles so don't often have a need to push the velocity. If I was shooting at 1000yds with a 308 I would want the highest possible velocity to try to keep the bullet supersonic as long as possible (all the way to 1000yds if I can).
-Federal primers tend to be very soft and will start to flatten in 30-30 loads which top out at 42,000psi. CCI primers just begin to flatten a tiny bit with an upper end 308 load which will be around 60,000psi. Other primers will show flattening at other pressures.
-Primer cratering (raised ridge around the firing pin dent) is often caused by oversized firing pin holes in the bolt face but can also be caused by a combination of too high a pressure and too soft a primer. In my experience CCI primers don't crater without an oversized hole even up to 65,000psi.
-Federal brass, likewise, can show ejector pin marks on the case head at a safe pressure for a cartridge like a 308 sometimes; definitely for something like a 270 win. Harder brass like military or Lapua wont show marks until pressure is dangerously high.
-Cases will start to stick in the chamber (stiff bolt lift, stiff extraction) at roughly the same pressure assuming it's the same rifle (different chambers will do it at different pressures) and the brass is of similar hardness in the neck/shoulder/body (the heads are significantly harder than those parts). Ganderites example of 75,000psi is in his rifle tells me he probably has a very smooth, polished chamber in the given rifle. I have a 308 with factory Remington chamber (tight but not polished) that gets a stiff bolt and sticky extractions only a little above max published velocities which probably means only a little above max rated pressure. Maybe 62,000-65,000psi? No way to tell for sure outside of a ballistic lab.
If you're looking to load to max it's best to use a chronograph and check for the max published velocity. It isn't a guarantee as there are still quite a few variables not taken into account but it's more reliable than looking at primers. For whatever reason I often find very accurate loads near the beginning to middle of load data in most modern rifles so don't often have a need to push the velocity. If I was shooting at 1000yds with a 308 I would want the highest possible velocity to try to keep the bullet supersonic as long as possible (all the way to 1000yds if I can).
I will be using Lapua brass. CCI primers with IMR 4064.I have pretty much everything I need except the chronograph. I would sure like a one. I seen one on the equipment exchange but I hesitated to long and it sold. Thats definitely the next thing Im going to need to buy because without It its all guess work. Any recommendations on a half decent one that not going to break the bank ?
41 of IMR4064 is the starting load. Actually .5 below.
Just use 175 grain data. Three grains won't matter.
If you're load is anywhere near 75,000 psi, you're grossly over loading. 75,000 psi is above the 70,000 psi standard 'Blue Pill' load for .30-06.
Just use 175 grain data. Three grains won't matter.
If you're load is anywhere near 75,000 psi, you're grossly over loading. 75,000 psi is above the 70,000 psi standard 'Blue Pill' load for .30-06.
