140 or 160? Now accepting advice.

[VikingsGuy]

I found an accurate load for my 25-06 with RL26 and 110 grain Accubonds.

I am a newbie at reloading and due to availability at local reloading store (and promises of temp stability) have started with a several Hodgdon "extreme" powders - I am going to start the 25-06 with H4831SC & H4350. I am working on 7mm08 with H4985 and Varget. If these don't shoot I will look into finding some RL powders.

 

[Dougfirtree]

To stir the pot a bit, why do so many people seem to feel that the 160 is a bad choice for the 7mm-08? Sure it's slow, but unless you're finding accuracy at the very top end of the 140's velocity range (as Buzz has), it doesn't seem to me to make a whole lot of difference. A 160 going 2500+ is pretty darn similar, in power, to a 140 going 2700+. It also bucks the wind better and probably penetrates better, on average. And, inside of 400 yards, it's still going to have enough velocity to open reliably. Seems like the only real disadvantage is trajectory.

After all, wasn't the 7-08's ballistic twin, the 7x57, originally developed to shoot 175's?

 

[MThuntr]

Good question I have no idea. It's probably just the idea of more velocity...that being said a 140 grain E-tip or TTSX will probably be loaded similarly to a 150/160.

 

[Gunner46]

Getting back to the OP's original questions......I have settled on the 140gr either in a Accubond, or the Ballistic Tip.

When I got serious about getting my Ruger 77 dialed in I 1st asked here on HT and that thread went on & on for months! What I got were dozens & dozens of debates as to what to try. But as you state a budget is a budget.....I get it.

I did spend money, and time, and effort buying different powder, (when it was hard to find) and wound up giving 60% of it away to friends when it didn't cut the mustard either in accuracy, or velocity.

Varget & RL-15 were hands down the winners with 120-150 grain bullets.

The weird thing with my rifle is that likes RL15 w/ 120's, Varget w/ 140's, and then RL15 again with 150's ! Go figure.

As far as the 120 Barnes goes, don't summarily discount it as a viable up to elk. Remember, it doesn't shed weight like a lead core so it will penetrate just as well as any 140.

I'd drop all considerations of a 160. You might as well be lobbing boulders with a catapult, They just can't maintain velocity for reliable expansion past a couple hundred yards... (that ought to draw some ire :hump: )

As far as the pressure issue debate goes, drop in on the Nosler forum and ask one of the guys to run a QL program for you. They are a pretty helpful bunch of Good guys who will keep you technically on the safe side of doing Stupid !

 

[belly-deep]

To stir the pot a bit, why do so many people seem to feel that the 160 is a bad choice for the 7mm-08? Sure it's slow, but unless you're finding accuracy at the very top end of the 140's velocity range (as Buzz has), it doesn't seem to me to make a whole lot of difference. A 160 going 2500+ is pretty darn similar, in power, to a 140 going 2700+. It also bucks the wind better and probably penetrates better, on average. And, inside of 400 yards, it's still going to have enough velocity to open reliably. Seems like the only real disadvantage is trajectory.

After all, wasn't the 7-08's ballistic twin, the 7x57, originally developed to shoot 175's?

The 7x57 was also developed for iron sights.

I think the 140’s and 150’s are best in the ‘08. You should be able to get 2850+ out of a 140. That is a nice velocity. Both fast enough and mild enough for good bullet performance. Sufficient SD for penetrating anything you would kill with the round. Really the question is why would you not choose a 140 or 150 in a 7mm-08? Just strikes a good balance.

Nothing wrong with 160’s but an awful lot of them are built to withstand a 7mm mag. Combine that will the a slower RPM and you have a load that will not kill as quickly as the lighter bullets. I doubt if you could find a circumstance where the 160’s offered an advantage over 140’s other than wind drift.

 

[JLS]

160s in a mono bullet would be tough because of the length of the bullet. If you are using a cup and core, it just depends on what you are looking for. I look for balance between velocity, and BC. If you range and dial everything, the 160 might be a great application so long as you get the velocity you need for bullet expansion in the ranges you hunt.

A well placed shot will kill as quickly from a light and fast bullet as it will from a slow and heavy bullet, including everything in between.

 

[1_pointer]

With that many accurate choices no reason to at the time, but at some point I plan on putting the theory to the test. I can only hope my work up of a 25-06 round for WY 'lope this fall is half as successful.

The new ELDX by Hornady would be getting a hard look from me for pronghorn out of a 25-06.

 

[Dougfirtree]

The 7x57 was also developed for iron sights.

I think the 140’s and 150’s are best in the ‘08. You should be able to get 2850+ out of a 140. That is a nice velocity. Both fast enough and mild enough for good bullet performance. Sufficient SD for penetrating anything you would kill with the round. Really the question is why would you not choose a 140 or 150 in a 7mm-08? Just strikes a good balance.

Nothing wrong with 160’s but an awful lot of them are built to withstand a 7mm mag. Combine that will the a slower RPM and you have a load that will not kill as quickly as the lighter bullets. I doubt if you could find a circumstance where the 160’s offered an advantage over 140’s other than wind drift.

Well, the reason to pick something else would be because my rifle shoots them really well;-)

In my rifle, 2800+ is only attainable at max loads of a handfull of powders. I've now tried several of them and gotten crappy accuracy. The best groups I've seen have been more like 2700. I think I just have a slow barrel. Maybe that's why it shoots the 160's so well...

 

[rammac]

Changes in velocity due to seating depth will vary by powder...each has a different burn curve which results in different pressures and velocities. It's hard to not discount the information provided because we have no idea of the sample size which very likely only a few bullets and uses only one double based powder. The effect may be completely different with a single based powder. I suggest loading for your rifle and making changes based on feedback it provides.

While I agree with your final recommendation I disagree with your description of how to view pressures and velocities.

The problem with the several of the comments in this conversation about pressures is that people are making the mistake of looking at too many variables at one time. All experiments should only be evaluated by changing only one variable at a time, saying that huronmtns' proof is questionable because different powders have different burn curves is false, he didn't change powders so changing powders has nothing to do with the data. Since huronmtns' experiment only changed the cartridge overall length then the results are valid, they might not be precise (due to dimensional variations or other uncontrollable deviations) but they are accurate and therefore the trend is valid. Not only that but his test results are in line with the well known physics of burning smokeless powder.

All cartridges have two factors that effect changes in the pressure (excluding powder brands and types);
1. The volume of the cartridge case.
2. The frictional forces that restrict the movement of the bullet

A cartridge is considered a closed vessel when you study the pressure, and as in any closed vessel, pressure and volume are inversely related, as one goes up the other goes down and visa versa. Assuming that the powder charge and type is kept the same, pressure is increased as the bullet is seated deeper because the usable volume of the case is reduced. The same amount of energy is being released in a smaller volume.

When the pressure builds inside the cartridge case it reaches a point where it is large enough to overcome frictional forces that prevent the bullet from moving. When those frictional forces are overcome by the gas pressure produced by the burning powder then the bullet moves forward and the pressure is reduced because the usable volume of the case is increased. If nothing restricts the movement of the bullet, other than the frictional forces between it and the neck of the case, then the bullet moves at a certain pressure. On the other hand, if the bullet is seated long enough to allow it to contact some part of the chamber then the resistance to it's movement is increased and it takes more pressure to move the bullet.

The chamber of a rifle has a portion called the throat, it is an area of the chamber that is tapered from the same size as the outside diameter of the case neck down to the inside diameter of the grooves of the bore. As a bullet is seated longer it makes contact with the throat, the lead of the lands, and finally the lands themselves. The bullet is basically being pressed in to a die with the lands eventually engraving in to the bullet's jacket. As the bullet is seated longer it will start to contact these chamber features and resistance to the bullet's initial movement will increase and the pressures and muzzle velocities will go up. The mistake people make when they say that seating the bullet deeper reduces pressure is that they don't base the length on a fixed reference. If you use a cartridge length that results in the bullet touching the lands as your fixed reference then yes, seating the bullet deeper will reduce pressures, but if the bullet was already off the lands and it wasn't touching the walls of the throat then no, the pressure will not reduce, it will in fact increase. Touching the lands increases the resistance to bullet movement by such a great degree that it far outweighs the effect of slight changes in case volume but once the bullet is no longer touching anything in the chamber then the usable case volume will become the controlling factor in pressure and velocity changes.

Some people find their best loads by making their cartridge so long that the bullet touches or is partially engraved in to the lands (seated in to the lands) and others find their best loads when the bullet is seated short of the lands (seated short by some amount). Seated in to the lands can, in some situations, improve accuracy since the bullet starts out by being held in alignment with the bore's axis, at least that's the theory. In reality, all rifle/bullet combinations are different and some chambers were cut closer to specifications than others so you need to test different configurations to find what works best for you.

 

[huronmtns]

To help clear up the interpretation of my chart data:

The Longest COL was measured and was .010" from contacting the lands. I did not want to contact the lands as this is a max charge and I did not want to see a pressure spike.

Also the sample size was 3 shots at each length. Statistically this is low but it is a level where early characterization can be observed.

Outside temperature was 30 degrees F.

I may repeat this test with Varget and 140 Gr Sierra Gamekings this weekend if the weather cooperates and if anybody is interested in seeing more results.

 

[BuzzH]

Well, the reason to pick something else would be because my rifle shoots them really well;-)

In my rifle, 2800+ is only attainable at max loads of a handfull of powders. I've now tried several of them and gotten crappy accuracy. The best groups I've seen have been more like 2700. I think I just have a slow barrel. Maybe that's why it shoots the 160's so well...

Going to ask the captain obvious questions, but your rifle is bedded, floated, yada yada?

 

[belly-deep]

Well, the reason to pick something else would be because my rifle shoots them really well;-)

In my rifle, 2800+ is only attainable at max loads of a handfull of powders. I've now tried several of them and gotten crappy accuracy. The best groups I've seen have been more like 2700. I think I just have a slow barrel. Maybe that's why it shoots the 160's so well...

When a gun won’t shoot well near max loads it usually means a gun problem.

 

[std7mag]

Buzz,
I'd suggest backing down.. Unless you have a 30" barrel, your about 200 fps fast for 140gr with Varget.
Your only 16fps slower than my 7mm-08 AI with RL17.

Viking,
Try Alliant Power Pro 2000. Gives decent velocity 2,800ish, and very low extreme spread and standard deviation.
"Temp stabil also."

 

[Dougfirtree]

Going to ask the captain obvious questions, but your rifle is bedded, floated, yada yada?

Yes, it's bedded and floated. The rifle in question is one of the newer FN Winchester m-70 featherweights.

For the record, I've decided to give the 140's another go. I ordered a box and I'm going to pick up some Varget tomorrow. If I end up going with the 160's eventually, it won't be for lack of trying. I took some of those old 160s I had left over from elk season to the range today for fun though. First group was 7/8"...

 

[BuzzH]

Buzz,
I'd suggest backing down.. Unless you have a 30" barrel, your about 200 fps fast for 140gr with Varget.
Your only 16fps slower than my 7mm-08 AI with RL17.

Viking,
Try Alliant Power Pro 2000. Gives decent velocity 2,800ish, and very low extreme spread and standard deviation.
"Temp stabil also."

Why? No pressure signs...and interestingly enough, the 2910 is from my wifes rifle with a 23" barrel. Shooting the exact same everything mine with a 24" barrel is getting 2850. Lots of people shooting 43.0 grains varget with 140 grain bullets. Velocity is jiving with ballistics calculations and verified to 750 yards with MOA come-ups. Not seeing an issue or need for concern.

Some of my brass I've loaded at least 6 times, primer pockets are tight, haven't trimmed brass yet...and just bump shoulders when I resize.

Not seeing the need to back off anything...and how do you figure I'm 200 fps fast? based on what?

Hodgdon is listing varget at 42.2 getting 2819 with a 24" barrel...seems reasonable to be over that with 43.0...I aint scared.

 

[BuzzH]

Yes, it's bedded and floated. The rifle in question is one of the newer FN Winchester m-70 featherweights.

For the record, I've decided to give the 140's another go. I ordered a box and I'm going to pick up some Varget tomorrow. If I end up going with the 160's eventually, it won't be for lack of trying. I took some of those old 160s I had left over from elk season to the range today for fun though. First group was 7/8"...

Don't fight the monster...go with the 160's if that's what shoots well.

 

[N2TRKYS]

Why? No pressure signs...and interestingly enough, the 2910 is from my wifes rifle with a 23" barrel. Shooting the exact same everything mine with a 24" barrel is getting 2850. Lots of people shooting 43.0 grains varget with 140 grain bullets. Velocity is jiving with ballistics calculations and verified to 750 yards with MOA come-ups. Not seeing an issue or need for concern.

Some of my brass I've loaded at least 6 times, primer pockets are tight, haven't trimmed brass yet...and just bump shoulders when I resize.

Not seeing the need to back off anything...and how do you figure I'm 200 fps fast? based on what?

Hodgdon is listing varget at 42.2 getting 2819 with a 24" barrel...seems reasonable to be over that with 43.0...I aint scared.

I ran your 43 grains of Varget load in my rifle and didn't have any pressure signs, either. Mine was slow with Varget, though. Big Game gave me mid 2800s with 140 grain Partitions. RL16 gave me 2800fps on the nose with 140 grain Accubonds. This is out of a 20" barrel. Both loads are accurate. Varget gives me 3000fps with 120 grain NBT with great accuracy, as well.

 

[BuzzH]

I ran your 43 grains of Varget load in my rifle and didn't have any pressure signs, either. Mine was slow with Varget, though. Big Game gave me mid 2800s with 140 grain Partitions. RL16 gave me 2800fps on the nose with 140 grain Accubonds. This is out of a 20" barrel. Both loads are accurate. Varget gives me 3000fps with 120 grain NBT with great accuracy, as well.

Those are some good numbers from a 20" barrel...that 120 BT load sounds like a dandy.

 

[Dougfirtree]

Well, I think I finally found an acceptable load with the 140 accubonds. I did some testing with H 4895 at 2.8" instead of 2.84" and seemed to have an accuracy node around 40 grains. Groups were about 1.5 inches. So, I played with seating depth and found that at 2.75" it would shoot about 3/4" and just a hair below 2700fps. I think I'm still below max, so I'm curious if I can shorten it a tad more and squeeze a bit more velocity out of it and keep the good accuracy (and pretty good velocity spread, too). It feels good to finally have some success with that bullet and the seating depth thing is making me wonder what would happen if I re-tried a couple other powders at 2.75".... It seems to like a big jump.

One thing that really surprised me (and reminded me of this thread), was the BIG difference the OAL made in velocity. This 40 grain load averaged 2585 at 2.8" and 2694 at 2.75" I would never have guessed that .05" would make such a big difference!

 

[huronmtns]

It's good to hear you are finding a solution for your rifle. Keeping records of your load data and results will help to figure out the pattern of what that rifle likes.
Remember to keep an eye out for pressure signs if you elect to go back and work with some of the other powders you have tried. Don't just make a jump of .050" and see what happens. Work your way in towards the shorter COL. I would really recommend measuring to the ogive for the greatest precision and consistency when working near Max loads.