Yew Tree 6mm Bullet
- Thread starter bendavies7
- Start date
Indeed but the ttsx has a plastic tip in the end which my bullet does not. Therefore (assuming they are the same shape which they’re not) the ttsx would have more bullet in the case than mine given the same COAL. That would more than account for the lack of a compressed charges given quickload puts the ttsx at 103% fill. Brass thickness variation in different manufacturers’ cases would account for that in any case.
Did I read this right, you are getting 3570fps with N160?
There are a few pics on the previous page.
baguio
Well-Known Member
Amount of propellant burnt 90.36%. Looks like the wrong powder choice to me or am I reading this wrong?
baguio
Well-Known Member
I rather meant munties and CWD size animals however that damage does look similar to what I have had with non-toxic.
Loler UK
Well-Known Member
3570 was during a ladder, not interested in running them that quick. One ladder was abandoned at a lower velocity due to pressure signs.
Quick load doesn't give you the true picture unless you can verify with an accurate chronograph and manipulate it. There are ways and means to get more out of slower powders IME.
If quick load tells you you should be getting 3150 and you're getting 3300 from the same charge measured with lab scales and confirmed on a lab radar & targets at multiple ranges there's clearly something the software doesn't know and you can be sure the pressure predictions are off too.
Even a dirty barrel will change the dynamics and cleaning can see an increase or decrease in velocity in my experience. the best way to test ammo is to shoot it, you can use all the software & theory in the world the there's a difference between I, T & A and the more T you come to understand the closer you'll get to predicting A. Every day is a school day
The load that I have 4 rifles shooting are all shooting the same charge and all generate between 3220fps - 3300fps.
After some further testing & tuning the ammo to make sure the quality is up to scratch in most rifles it will go to be cip tested and be available for sale through the RFD I've started working with.
No I don't think your reading this wrong, 160 is way to slow for the 243.
How many grains of 160 were you using in the ladder load to get to 3570fps?
Loler UK
Well-Known Member
Plenty
Sorry I don't share how far I push ladders or what load I settle on, like I said some ladders were abandoned early on some rifles. The ladder started at 40.6. and like I said the node that was settled on was with significantly less powder.
160 is listed / recommended by certain bullet manufacturers for the .243, even for 70gr projectiles: 243 Winchester Load Data - Nosler
If quick load tells you you're getting a 89% burn with X generating 3100fps and you're getting 3300fps with X you know something is going on. This is the limit of the T that some people apply not realising what the A is.
Unburnt powder can cause serious issues, duly noted
I'm developing with other powders for these same bullets, 550 150 and other brands, a fast powder has the advantage of being useful in shorter barrelled rifles getting a better burn, but like I said, there are ways and means to get more out of slower powders.
If you think that these bullets have the same release, friction and pressure characteristics as a barnes you're missing the mark to begin with, not to mention that you are doing so without asking any questions about neck thickness, ID, crimp, jump, lands angle, I suggest you load them up using your data varying the neck tension and crimp pressure and pay to have them tested to cip standards and return with the A to back up your T with 'it's way too slow'
There are allot of variables that are not on that quick load data you posted.
Sorry I don't share how far I push ladders or what load I settle on, like I said some ladders were abandoned early on some rifles. The ladder started at 40.6. and like I said the node that was settled on was with significantly less powder.
160 is listed / recommended by certain bullet manufacturers for the .243, even for 70gr projectiles: 243 Winchester Load Data - Nosler
If quick load tells you you're getting a 89% burn with X generating 3100fps and you're getting 3300fps with X you know something is going on. This is the limit of the T that some people apply not realising what the A is.
Unburnt powder can cause serious issues, duly noted
I'm developing with other powders for these same bullets, 550 150 and other brands, a fast powder has the advantage of being useful in shorter barrelled rifles getting a better burn, but like I said, there are ways and means to get more out of slower powders.
If you think that these bullets have the same release, friction and pressure characteristics as a barnes you're missing the mark to begin with, not to mention that you are doing so without asking any questions about neck thickness, ID, crimp, jump, lands angle, I suggest you load them up using your data varying the neck tension and crimp pressure and pay to have them tested to cip standards and return with the A to back up your T with 'it's way too slow'
There are allot of variables that are not on that quick load data you posted.
flytie
Well-Known Member
I will agree with Loler, N-160 is a fine powder for some bullet weights in the .243 Win. But, and it's a doozy, quickload may not be accurate but it is a very good guide. I have adjusted the table to give you the benefit of a 24" barrel, also a fox bullet 3gr smaller than the one you quote, but similar in shape. Now I have read the articles on monolithic bullets needing less energy to start their travel up the barrel, due to the smaller bearing surface of the mono-metal bullets, thus giving a slight increase in velocity, but even so your quoted figures have made my eyebrows raise. Bear in mind I have used N-160, RS-76 and many other powders to push bullets out of my .243, many of these being my trials with the supposed non-toxic bullets, all of which have been chronographed with my Magnetospeed V3, I have never managed to achieve speeds from N-160, out of my 570mm Sako barrel, anywhere near your quoted 3,570fps, especially with N-160. 
S.
S.
jon2
Well-Known Member
What charge weight of N160 are you using which produces 3570 feet with that bullet?
jon2
Well-Known Member
I'd be interested to hear how. Could you please elaborate?
The reason for the question was that I am using a cartridge based on the 243/308 using under bore bullets with drive bands and was looking for answers as to how it is possible to use 160 effectively as I have quite a few kilo's of it.
Ronin
Distinguished Member
If the Yew tree bullet (sorry the names has unfortunately connotations with Operation Yew Tree for me )
If the bullet in question has “drive bands” and the body is land diameter (drive bands groove diameter) then there will be significant pressure reduction and likelihood of higher than predicted VO
I’ve seen this time and time again with my own experience of using LTS with drive bands
Often seeing 300 FPS over predicted PMax or equivalent software
If the bullet in question has “drive bands” and the body is land diameter (drive bands groove diameter) then there will be significant pressure reduction and likelihood of higher than predicted VO
I’ve seen this time and time again with my own experience of using LTS with drive bands
Often seeing 300 FPS over predicted PMax or equivalent software
The picture does not show drive bands..
flytie
Well-Known Member
I agree wholeheartedly; Using N-160 in Lapua brass my results were this, the predicted QL velocity of my chosen load was 2,943 fps from my 570mm barrel but the chronographed velocity was an average of 147 fps higher, just as various articles on reloading with mono-metals predict. But this is with a powder load and bullet seating depth which needs a drop tube to be used to achieve the desired powder charge that gave me the best accuracy from N-160. The load was 974 Bar below P-Max. However, I did find a different powder gave me my best results, but all rifle barrels are individuals.
S.
jon2
Well-Known Member
I’d also like to know how he explains the 120% case fill and also the voodoo magic used ref “ways and means to get more out of slower powders.”
Just for the record, most people seem to be running around 42.5grains N160 for around 3200-3250 fps. The fastest I have had the bullet going from a .243 win is 3380fps with 42.6 grains N550. That for me was a bit punchy and I wouldn’t have wanted to use it on a hot summer’s day given N550’s temperature sensitivity.
