Advice on bullet seating depth Berger 95 grain hybrid

[merbeau]

Hi

I recently moved to an area where it is possible to do some rifle shooting. My reloading experience for the most part has been limited to Bullseye pistol and skeet shooting.

I am trying to build a load for my older Browning Safari in 243 caliber that has a 1:10 twist rate. I have selected the Berger 95 grain BTHP hybrid bullet as my starting point. I am using Nosler brass.

I cut two slits into the neck of one piece of un primed brass and inserted a bullet. I then placed the blank round into my chamber and slowly closed the bolt. I then slowly backed the seated bullet out and came up with a COL of 2.695 inches which is below the SAAMI published maximum. I then tried placing this round into the rifle's magazine and it did function.

Two questions

First is this technique I just described considered touching the lands? I have read where Bergers like to be seated into or close to the lands, however, their advertisement for his bullet says it is indpendent of seating depth.

Second. Should I start with this length or slightly less so as not to obtain pressure spikes?

Thanks

Robert

 

[Freedom2live]

Start with minimum grains as prescribed by cookbook. Seat ten round at various coal. Clean rifle after 10 rds everytime . Look at your cases with a magnification loop or whatever, for excessive case budge or head separation , discoloring cuts and rips . Then measure your group from 100rds edge to edge and subtract bullet diameter for total groups size. Shoot at different targets and remember aim small miss small.. Let me know how you did..

 

[lever-hed]

You have the basic premise down. You should remove the ejector for that process to ensure no false readings. You can also try neck-sizing the 'dumby' case VERY gently and slightly to get the best 'grip' on the bullet so you don't have to destroy a case.

What are you using to measure your "COL" ? You should be measuring to ogive (not tip), the ogive is more consistent dimensionally. (just verifying)

Those bullets don't require you to load on the lands. That will be beneficial to you since you have a magazine. (even VLD's don't necessarily need to be loaded on or jammed into the lands -- read the 'sticky' thread on the berger VLD bullets.)

 

[merbeau]

Level-head and Freedom2live

Thank you for replying. I measured the COL to the tip and not the ogive.

The statistics on the Nosler brass was remarkable. Less than 1.0 grain difference between maximum and minimum and 90% within 0.3 grains of each other.

Another determination and question:

For volume I used the water technique and found a mean of 52.0 with a range of 52.2 to 52.3 grains. The volume occupied by the bullet is case length (2.032) and bullet length (1.07) then subtracted the overall COL (2.695) which is 0.407 inches for bullet seating. Next calculate the area of the bullet's cross section. For a .243 diameter bullet, that is (0.2432 ÷ 4) x 3.1416 = 0.0464 square inches. Multiply that area by the seating depth gives you the volume 0.0188 of the case occupied by the bullet, but it is in cubic inches. To convert cubic inches to grains of water, multiply by 252.8 grains of water per cubic inch which is 4.774 grains. Then subtract from case volume 52.0 – 4.774 = 47.23 grains. This a little off because the Berger bullet is a boat tail.

Question: So any charge larger than 47 grains would be compressed?

 

[dakota1tn]

I just set up a 243 with this same bullet. This Savage 11 shot best at 20 thou. off the lands and 46 grns of H4831. Shoots a1/4 in groups at 100. When starting with a new gun I load 2 each at touching .005 .010 .015 .020 and so on out to .040. If two touch I load two more and see what happens. This seems to be the fastest most affective way I have found. I also tried them in another 243 and tried diff depths and they didnt do as well.

 

[merbeau]

Dakota1tn

Thank you for the information. Trying to find any data for this bullet is not an easy task. I will use this information in my testing scheme. I went back and read the Berger notes and it does say not as sensitive as other Bergers like the VLDs to seating depth. Your information looks as if there is a difference.

My reloading room has IMR 4350, 4064 and 4320 as wells as Alliant RL17 but no H4831. I am hoping one of those powders will perform well although Hodgdon told me not to use 4320 because of none of their data is current and more than likely the charge will not fit into the case.

Robert

 

[ShootnMathews]

I don't have any load data in my book on it but my friend uses 4064 in his 243 with great success. I use varget and h4831

 

[Gene]

Go to Sinclair and get a bullet comparator nut which will measure from the ogive to the head of the case while it rests on lower arm of your caliper. Load a dummy round to that length, clean the bullet with 0000 steel wool, run it in the chamber, and slowly extract. Look closely for small contact marks from the lands. Write it down, that will be your kissing point. You can further jump or jam bullets from that point as needed.


My 6BR Dasher likes the 105 gr. hybrid bullet to be jumped .015". Many others report the hybrids like to be jumped.

 

[merbeau]

ShootnMathews

From an initial literature search it seems that IMR 4064 and 4350 are most often mentioned, however, H4831 comes up quite frequently. I am guessing because these powders have been around for a long time whereas some of the others such as Varget are newer additions.

 

[merbeau]

Gene

Ok that is great information. At least there is a tool, a source and technique.

 

[Joe King]

Your going to find that the Classic hunters are very forgiving about seating depth. In my experience with then them, they just shoot well, I don't believe I've seen a group yet that measure MOA or larger with them through out the load workup.

Your not going to find much info on these bullets as they first hit the stores last Sept. My adives is find a seating depth that allows for magazine use the follow "Dan Newberries OCW" process.

When I worked up a load for them in my 243 last fall I had all of 2 weeks to get it done so I used a different method that gave me a good load in less than 20rnds (IIRC it was 12)

 

[lever-hed]

merbeau,
You need to get yerself one of the reloading manuals, it will give you all of the data you require, including reloading techniques, etc. Try emailing Berger and they may send you data for the .243.. they did for me..
be careful, its addicting..

Loading Manual | Berger Bullets

 

[merbeau]

Ok, I have an older Berger manual that was published before the new hunter hybrids came out and three others Sierra, Speer and Norma that I have used for loading all of my pistol calibers (32 SW long, 32 ACP, 380 ACP, 38 special and 45 ACP and 9mm). I must admit I have been too cheap to buy the new Berger manual with all the money being spent on rifle reloading supplies. I have emailed Berger; however, have not received a reply as of today - 8 March 2013. They may inundated just like every other provider in the market today.

I did read the article by Dan Newberry and he seems to indicate to find a length that still will allow your magazine to function and somewhat downplays the importance of seating depth.

I have been amazed at all of the literature and variables for rifle shooting much more so than for pistol. And the arguments over many of these variables such as case weight are on opposite sides of the spectrum whether or not it is important to accuracy. I was reading a debate on case weight on another forum where two authors started name-calling each other over the issue.

The bullet comparator came in today and I used the suggestion of polishing the bullet with steel wool and reinserting it into the rifle. I looked on the bullet and very faint lines could be seen. I then placed the blank round into the comparator and the caliper read 2.1571 inches. So is this the starting depth in which to vary the seating?

 

[dakota1tn]

That is your starting point. Now load a couple at that depth to shoot and start backing of .005 at a time you will most likely find the sweet spot with 40 thousands.