Newbie here Hi everyone

[Scottish Highlander]

Hi everyone, just like to introduce myself and ask a few questions related to reloading. I tried the search engine but not really coming up with the correct answers

I'm from Scotland obviously.....game keepers son and have been in the shotgun/rifle culture for my whole life but I have decided to venture into reloading for cost and accuracy reasons.
I reloaded some brass with IMR 3031 to push a Nosler 150 gr BTBT. I found online a recipe on IMR's web site with a load from 40.2 grains up to a compressed load of 43.5 grains. I ended up going with a 42 grain load and it was a 1/4 inch group @ 100yards. I'm shooting with a 308 Tika T3 hunter through a Smit and Bender 8x50 scope with a wildecat suppressor. Factory ammunition would never have a group like that!!!

1st Question is and I am sorry if it has been asked 100 times over but can you use 150 grain bullet of any manufacturer with this load. The nosler is 9.7 grams in weight static on the digital scale. I presume I can use a Hornady 150 grain round with this load data to ?????? providing it is of the same weight example.

2nd question is I made 2 loads after confirming where exactly the Lands was according to the bullet and making up a dummy round. My OAL was 70.0 mm dead. This load gave the 1/4 inch group @100 yards.
I then seated a new load at 69.0mm wich is clearly 1mm back from the Lands further and my group fell out all to a 3 inch group. Is this a normal outcome and you have to find the sweet spot for your rifle to tighten up the group. I know that the 70.0mm OAL is 3mm back from the Lands...

Thankyou for your time in advance and sorry if the questions are a bit repetative

Jamie

[hooligan1]

Welcome to this forum, Highlander,
1. You will have to test different bullets with that powder to find data your looking for.
Being different, two bullets weighing the same doesn't mean they will measure the same in relation to your OAL.
2.Yes a very minute difference in OAL can make a difference in pressures hence the change in accuracy.
good luck and happy shootin dude

[Scottish Highlander]

Thanks hooligan1, I really like the Nosler 150 grain bullet and shot 3 Red deer hinds with it in 1 sitting last Saturday and its a good stopping round. My next round that I will try is the Hornady 150 grain BTBT but I am struggling for a recipe on the load. Well thats not strictly true. I can find recipe's but not using the IMR 3031 powder and I would rather stick with 1 powder just now. Hence my question with regards using the same recipe from the Nosler load I have.

Thanks Jamie

[SL1]

From Nosler Reloading Guide #6 for .308 Winchester cartridge loaded to overall length of 2.810" with 150 grain Nosler bulllets using IMR-3031 powder in Nosler cases with Federal 210M primers (velocities from a 24" Lilja barrel with 1-in-10" twist):

41.0 grains gave 94% case fill and 2600 fps
43.0 grains gave 98% case fill and 2740 fps
45.0 grains gave 103% case fill and 2880 fps

Hornady Handbook of Cartridge Reloading 8th Edition does not provide data for IMR 3031 powder in this cartridge for bullet weights over 110 grains.

Comparing loads for powders that do appear in both manuals indicates that max loads for the Hornady 150 grain bullets are sometimes substantially higher and sometimes sustantially lower than in the Nosler manual. For example, IMR-4895 has a 1.9 grain higher max for the Hornady bullet, while IMR-4064 has a 3.1 grain lower max. But that may be because Hornady choose not to publish compressed loads and the Nosler load showes 107% case fill with this max and 99% fill withn the IMR-4895 max. In general, for the powders appearing in both manuals, the ones that do not have compressed max loads in the Nosler manual seem to have higher max loads in the Hornady manual, while the powders that have the compressed max loads in the Nosler manual have lower max loads in the Hornady manual.

This indicates to me that the Hornady bullets can be used with slightly higher charge weights than the similar Nosler bullets. That matches my own experience with these two brand in the .270 Winchester cartridge as well as some of the things I have read in the literature. The main difference is that the Nosler bullets have substantially thicker jackets, which tends to increase peak pressure.

So, I would say that you can probably start safely with the Nosler "start" load under a Hornady bullet, but be careful about going the other way. Work-up carefully, and try not to exceed either the Nosler max load or the Nosler max velocity with the loads from your gun. If your barrel is not 24" long, then adjust the expected velocities by about 50 fps per inch of barrel length difference.

Perhaps somebody with an older Hornady manual can check and see if Hornady ever produced pressure-tested data for IMR-3031 with this set of components. I will not be where my older Hornady manuals are located until Monday.

SL1

[Scottish Highlander]

150 GR. NOS BT IMR 3031 40.2grn 43.5C grn

150 GR. NOS E-TIP IMR 3031 39.3grn 42.8 grn

155 GR. SIE HPBT IMR 3031 39.5grn 43.2C grn

165 GR. HDY SP IMR 3031 39.1 grn 41.6 grn

168 GR. BAR TTSX BT IMR 3031 38.0 grn 41.5C grn

This is the load data from IMR Hodgdon web site. This is a large proportion of the 3031 data. Throughout the load data a 41 grain load would be a good starting point as far as I can see for a Hornady 150 grain load. The heavier the bullet weight the less the grain of powder. Obviously this is to counter act for pressure build up in the rifle. I think I am going to have to do some more trawling of the web and reloading manuals to try and find a load to confirm that it will be ok. Either that or it is just going to be a new tub of powder

Thanks Jamie

[SL1]

From Hornady Handbook of Cartridge Reloading, 4th Edition.

For .308 Winchester cartridge and IMR 3031 powder under 4 different Hornady 150 grain bullets, using Federal 210 primers in Hornady cases, with velocities from a Wincheter Model 70 rifle with a 22" barrel, 1-in-12" twist:

36.3 grains gives 2400 fps
37.9 grains gives 2500 fps
39.6 grains gives 2600 fps
41.2 grains gives 2700 fps and is max load

The overall cartridge lengths vried with the bullets, and were as follows:

#3031 SP col = 2.750"
#3033 BTSP col = 2.756"
#3035 RN col = 2.520"
#3037 FMJ col = 2.777"

That max load is substantially less than the max load listed in the Nosler manual for Nosler bullets. That is a surprise to me, since my experience is that Hornady bullets can usually use a little more powder than Noslers, all other things being equal. The data in the 4th edition is copyrighted 1991.

SL1

[hooligan1]

What kind of accuracy and repeatability to you get from 3031, in the .308? Also have you tried the Barnes TTSX line of copper bullets? The Nosler bullets have always killed nicely for me, but just to have some other bullet my rifle would like , I tried those dudes in my .270 win, using the same powder and charge weight that my rifle shoots well with 130 grain Accubonds, and it shoots them right to the same POI basically. I like to handload and test bullets...

[Unclenick]

Scottish Highlander,

You seem to be describing a load moved to the lands. Note that touching the lands as compared to as little as .7 mm off the lands can increase pressure 20%. That causes a substantial difference in velocity and barrel time, which can easily move you off a barrel time sweet spot.



Any time you change a non-powder component in your load recipe, be it primer, case, or bullet, reduce the charge 10% (5% is OK for the primer) and work it back up in 2% steps, watching for pressure signs. That's just six rounds total shooting in a quick check, so not much of a burden for safety. I recently read about some older testing in a pressure gun in which same-weight bullets were used and all worked OK until they tried a Speer bullet that drove the pressure up substantially. Speer said their jacket was thicker. I suspect their ogive radius was shorter, too.

Try locating a best seating depth for your bullets. It is not uncommon to find more that one and sometimes the second one is a lot further back behind the lands than you'd expect. Read this. Also read item 3., here.

If you would like a good general approach to identifying accuracy loads, take a look at Dan Newberry's OCW method. We can always add more tools and toys to your load development list for further refinement later. As you are shooting .308, you might also enjoy this.

The reason different cartridge overall lengths (COL) are needed with different bullets has to do with profile differences. Below is an exaggerated example of two different bullets loaded to the same distance off the lands.

[Bart B.]

Unclenick, your Pressure Change vs Seating Depth table shows a pressure change per .001" of seating depth for the first .050" off the lands of about 18 to 20 psi. It changed about 900 psi over .050" which pleases me 'cause I've been told that and read that for years the psi change per mil is very, very small. Never seen any "good looking" data to support it until you posted that table. Where'd it come from?

And your line stating:

As you are shooting .308, you might also enjoy this. http://www.accurateshooter.com/shoot...es-from-bipod/

is a link to a guy who loads his .308 ammo with the same techniques with an old standard full length sizing die with its neck lapped out; just like I have suggested to folks over the years.

Would you like an attaboy, kudo or some other accoloade for putting up good stuff like Slamfire got? Doesn't matter; they're already on the way......thanks.

[Unclenick]

Thanks for the offer, but I have my wife's repeated assurances that my head is fat enough already.

The plots I combined and curve fit to are in the old U. of M. study done by Dr. Lloyd Brownell in 1965. Harold Vaughn referenced the study in his book, Rifle Accuracy Facts, but suggested that because Brownell relied on the Lame Theorem for hoop stress and strain on an infinite cylinder to calibrate his gages, that his numbers were likely about 20% high. So I knocked the Brownell numbers down 20% for that plot. Subsequently, I've had some other data to suggest Brownell probably wasn't quite as far off as Vaughn suggests, but have not redone the plot, as the difference will simply be proportional. Just allow that the changes it shows may be small by maybe ten percent or a little more. Not enough to change anything in principle, though.

Brownell suggests the explanation for the curve shape is that deeper seating allows more gas to bypass the bullet before it moves far enough forward to obturates the bore, thus putting a brief stall into the build-up of pressure. At the same time, that deeper seating is reducing the powder space. The former dominates to the left of the pressure minimum on the curve, but the latter comes to dominate to the right of the dip.

Two things to note: One is that the bullet used by Brownell was a round nose design, and a spire point is going to cut the flow off over a longer span, assuming his theory is correct. The other is that, unfortunately, Brownell did not test an actual jam into the throat, to check the static friction theory of pressure rise caused by a bullet in the throat. Light contact with a leade cut to different angle than the angle of departure of the bullet ogive off the bearing surface won't see much of that because the contact area is then so small.

Note below a disagreeing plot from RSI's web site (reproduced here with Jim Ristow's permission) showing a larger change in pressure over a 0.030" shift back from land contact. The upper three traces are "in contact with the lands", but how hard the contact is was not mentioned (could be a jam), while the lower four are 0.030" off the lands. In this case it works out to 250 psi difference per thousandth. Unfortunately, there's no way to tell whether being, say 0.005" off the lands would have produced something closer to what Brownell's curve looked like up to that point.

Some further testing is needed. I may get to do some of it this summer in .30-06, but with either 175 grain MatchKings and 150 grain Hornady FMJ's. I have one of the Pressure Trace instruments, but just wish it had more than 8 bits of resolution. The numbers on the plot below should really be rounded to the nearest 200 psi to better represent the resolution limits.