Starting Reloading - First Bullet Seating Depth Test Results

[thor447]

I recently started reloading as some of you may know (by mountain of questions in other threads). I've been making some rounds and doing some very non-scientific testing lately (Lack of other equipment - chrono, etc.). I learned these past couple of months that the standard RCBS seating die I had does not offer the ability precisely set the bullet seating depth. The adjustment screw on top is not precise and I now see the value of getting a high quality set of dies. With this new knowledge, I purchased a set of Redding Type S match dies. I decided to do some testing with bullet seating depth with my SMK 150gr 6.5 rounds.

Rather than buy a new gauge to measure my distance to the lands, I made my own, which has worked out very well. My measurement on my X-Bolt from the closed bolt face to the lands is 2.2105". I made 5 groups of 5 rounds, all with the exact same load (40.6g of H4350), same lot of once fired brass, etc. The only variant was the seating depth.

I went to Lexington this afternoon to do some testing at 100 yards. Here's the results.

5 groups were: .000, .010, .020, .030, and .040 off the lands. I had a flier on the .020 and .040 targets. Those were completely shooter error. The .030 group is horrendous. I thought I had good form and the shots felt good, but the pattern speaks for itself. I'm just chalking it up to my rifle DOES NOT like .030! Pics are below.

.010 and .020 were good, with .010 clearly being the best. Honestly, when I shot the .010 group, the first group as the two shots to the left. I made a slight adjustment to the scope and put the next three a little high. Hindsight tells me this was a stupid move, and I should've shot all 5 without changing anything. I'm confident that those 5 rounds would've all been clustered together if I hadn't made any changes. I think .010 is my number. I may load up some .015 and see what they do, but the .010 is good enough for me so I may want to leave well enough alone. Now I just need to get myself a chronograph.

 

[Dumpstick]

Several thoughts.

First, as you figured, never make scope adjustments during that type of testing. It will distort the results.

Second, I like the idea, but I think you need more rounds on a target. Minimum 10, but more is better. Take your better loads, and shoot at least 10 per target. You can get a better idea of the grouping that way.

Third, the dies. RCBS can be precise, but they aren't benchrest dies. Look at the Sinclair/Wilson hand dies, with an arbor press for precision.
The press is a one time purchase, the dies are relatively inexpensive after that.

Dies
https://www.brownells.com/reloading...hamber-type-bullet-seater-dies-prod36168.aspx

Press
https://www.brownells.com/reloading...e-presses/sinclair-arbor-press-prod37764.aspx

The whole setup with one die can be less than one set of other dies. After that, each cartridge die is much less than comparable threaded precision dies.

 

[swampratt]

Great job.
Looks like you are on your way.
I do not shoot 10 shot groups..I suppose if the gun were going to be used in a bench rest match then that or more could be a benefit as you could sort brass by which ones make a flier.

The way i like to do it is like you shoot 5 and sometimes I just shoot 3.
But I will shoot that same load of 5 or 3 many different trips to the range ..I will pick days in the sub freezing and days in 100+ temps and see if the load holds together.
Once I have a load and am confident with it i will make a box of 20 or 50 of them and go hunting.
I am not a bench rest shooter.
But I do like my shots to be on the money.
That goes for cold bore first shot of the day. It better be darn close to the rest of the shots.
No fouler shots allowed for a hunting gun.

I have had good groups at 100 yards fall apart at 200 and many of my guns now shoot in the 3/4" center to center at 100 yards which does not sound good but the same load will shoot 3/4" at 200.

 

[Jcann]

@swampratt is correct and you don’t need better dies or an arbor press to create accurate ammo. First off stop changing seating depth for now. You should first work towards what is called and optimum charge weight “OCW”. Basically make 5 loads with the same powder charge and bullet seating depth. Create 5 more by adding 0.3 grains to those 5 and so on and so forth.

Example
5 rounds w/42.6 grains @2.267” cartridge base to ogive (CBTO)
5 rounds w/42.9 grains @2.267” CBTO
5 rounds w/43.2 grains @2.267” CBTO
WATCH OUT FOR PRESSURE SIGNS, CRATERED PRIMERS/STIFF OR HARD BOLT LIFT/PIERCED PRIMERS. STOP SHOOTING IF ANY OF THESE OCCUR

Load up about 5 different total charge weights and shoot them. Hopefully you’ll be able to find one string of fire that shows promise. If you do, now you can start trying to fine tune it by adjusting seating depth. I usually start out with my CBTO set to kissing the lands and I’ve never had to reduce this length more than 0.002”.

But remember this, there is no substitute for a good barrel.

 

[thor447]

@swampratt is correct and you don’t need better dies or an arbor press to create accurate ammo. First off stop changing seating depth for now. You should first work towards what is called and optimum charge weight “OCW”. Basically make 5 loads with the same powder charge and bullet seating depth. Create 5 more by adding 0.3 grains to those 5 and so on and so forth.

Example
5 rounds w/42.6 grains @2.267” cartridge base to ogive (CBTO)
5 rounds w/42.9 grains @2.267” CBTO
5 rounds w/43.2 grains @2.267” CBTO
WATCH OUT FOR PRESSURE SIGNS, CRATERED PRIMERS/STIFF OR HARD BOLT LIFT/PIERCED PRIMERS. STOP SHOOTING IF ANY OF THESE OCCUR

Load up about 5 different total charge weights and shoot them. Hopefully you’ll be able to find one string of fire that shows promise. If you do, now you can start trying to fine tune it by adjusting seating depth. I usually start out with my CBTO set to kissing the lands and I’ve never had to reduce this length more than 0.002”.

But remember this, there is no substitute for a good barrel.

Thanks. I've been doing that with my previous range trips. Obviously without a chrono it's almost trivial, but I've found that the best load I have made thus far, without showing any pressure signs was at 40.6 grains of H4350. 40.9 showed a a minor sign on one round and 41.2 showed signs on the first two rounds so I stopped shooting those. That's why until I get my chrono (which will be soon), anything I shoot will be with the safe load at 40.6 that I've established.

 

[Dumpstick]

Of course one doesn't need an arbor press and special dies to seat the bullets. The OP commented on the RCBS dies not being precise enough, and I offered a different approach.

learned these past couple of months that the standard RCBS seating die I had does not offer the ability precisely set the bullet seating depth. The adjustment screw on top is not precise and I now see the value of getting a high quality set of dies

One thing I've learned in the years I've been reloading - ask 10 reloaders a question, you'll get 15 answers.

There is most certainly more than one way to skin this cat.

 

[swampratt]

I have made ammo and shot over the chrony and have them within a 5 fps of each other and some in a 30-30 shot 3 exactly the same velocity and the other 2 were within 4 fps.
They were not accurate..
Barrel whip can point the bullet in a different spot but give the same FPS on a chrony.
I decided to shoot paper to work up loads and leave the chrony at home.

But I was also working up loads at 200 yards at that time and then test the good ones at 300 yards.
100 yards i felt was wasting my time and reloading components.
You may have different results.

 

[Okie4570]

Thanks. I've been doing that with my previous range trips. Obviously without a chrono it's almost trivial, but I've found that the best load I have made thus far, without showing any pressure signs was at 40.6 grains of H4350. 40.9 showed a a minor sign on one round and 41.2 showed signs on the first two rounds so I stopped shooting those. That's why until I get my chrono (which will be soon), anything I shoot will be with the safe load at 40.6 that I've established.

Chrono is just icing on the cake for load development imo and not needed to shoot sub moa groups.. You're already using loading manuals of some sort so you know the approximate velocity at the muzzle and at 100y. Keep up with your consistency on the reloading bench and procedures as that's where the accuracy comes from as long as your rifle, optics, rest and you do your part when squeezing the trigger. I think back to all of the reloading my dad and his friends did in the 60's through the 80's and the only way they had any idea how fast their loads were was from what was printed in the manuals. That didn't keep them from having rifle after rifle and load after load that could produce dime size groups or smaller. Now when you start shooting long distances and want an accurate go to chart for your loads, then a chrono is needed without a doubt.

 

[swampratt]

Here is a little reading that is interesting.
http://forum.accurateshooter.com/threads/1000yd-benchrest-load-development.3932801/

 

[Calamity Jake]

A target like this is better for group testing as you can put the scope cross hairs in the exact same place for every shot
and have many different groups on the same target.