.303 advice

[Dougan]

Update: Some problems solved, but another one found...

My father rienforced the bench - There is virtually no 'give' (just a tiny bit in the press itself), and as long as I'm gentle with the seating, it's consistent.

And I made a stand for the powder dispenser from some of the worktop cut-offs.

I think I also found the reason for the neck tension problem - My error...I cleaned the inside of the necks after I'd resized them - I was using a stiff PB brush in a drill, and it may have opened the neck up a tiny bit. This time I cleaned the necks before I resized them, and found the tension better (not as easy to pull with the kinetic hammer).

Ovenpaa: I have the neck measurements...

On the cleaned and sized cases (measured very close to the top of the neck) the inside neck averaged at .3075, and the outside at .3335

On the inside of the neck, of cases that had been cleaned after sizing the average was .309 ...could this small difference have altered the neck tension?

Then I found a different problem - dispite the press being sorted, I was still getting inconsistent COAL measurements ...only up to 10 thou either way of what I was trying to do - but I found that the only way to get them spot on was to start a little long, and then use the screw at the top of the die to increase the depth of seating manually each time. I've looked at the thing that stops the bullet in the die, and it holds the bullet about a third of the way down (as opposed to the tip) - is it possible that the bullets vary in shape, and so stop in the die at different depths?? And if so what can be done to increase the consistency so you don't have to tweek each one indiviually?


On the major plus side - they shot very well. The conditions on Saturday were perfect for testing (no wind at all), and resting on a sand bag got some reasonable groups.

I tryed some 38 grs aswell this time. I cocked up the first test by having to alter the sights - but once sorted shot 5 38s and 5 39s:

Shots 1 to 5 were 39gr, and 6 to 10 were 38gr - as I'm using open v sights at 200 yrs I was happy with both groups, and couldn't say if one load was better than the other. I marked it on a TR 300 card, but on the 200yrd 'tin hat' target I was shooting at they were all in the bull

So that just about does it - apart from a few improvements to the reloading process, I've got a 200 yrd load that I'm happy with...now I've just got to see if I can keep them in the bull without the sandbag :)

[Steve]

How odd...thats excally the same way i reinforced my reloading bench!

Great minds think alike and all that jazz. :cheers:

With regards to bullet seating though.The benches rigidicty (is that a real word or have i just invented a new one?) only made a difference with 357mag when i have to pull hard to crimp the case,but no difference with just seating the 303.

[Dougan]

How odd...thats excally the same way i reinforced my reloading bench!

Great minds think alike and all that jazz. :cheers:

With regards to bullet seating though.The benches rigidicty (is that a real word or have i just invented a new one?) only made a difference with 357mag when i have to pull hard to crimp the case,but no difference with just seating the 303.

Yup same for me on the .357 too - a little more pressure needed to apply the crimp...where as the .303 seating requires very little pressure...

To great minds...and great scores! :cheers:

[Robin128]

Good posts Dougan.

[ovenpaa]

Yes, some very good posts indeed :goodjob:

[rox]

I was still getting inconsistent COAL measurements ...only up to 10 thou either way of what I was trying to do - but I found that the only way to get them spot on was to start a little long, and then use the screw at the top of the die to increase the depth of seating manually each time. I've looked at the thing that stops the bullet in the die, and it holds the bullet about a third of the way down (as opposed to the tip) - is it possible that the bullets vary in shape, and so stop in the die at different depths?? And if so what can be done to increase the consistency so you don't have to tweek each one indiviually?

There can be slight variations in bullet length, and most of the variation will typically occur near the tip. For seating depth measurements the measurement should be taken to the ogive since this will provide a more consistent indication of the length of travel before engagement into the lands, which is what needs to be consistent to obtain repeatable pressure buildup. Of course, if you feed from a magazine the maximum overall length is also important.

Gear_Stoney_Point_OAL_interiorWEB.jpg (15.08 KiB) Viewed 1478 times

You can use a comparator attached to calipers to measure to the ogive. Comparators are caliber specific. If you measure chamber dimensions, e.g. with an OAL gauge (aka 'Stoney Point'), always use the same comparator as you use to measure your loaded rounds, and take measurements with a number of bullets to avoid basing your loads on measurements obtained with a bullet at one end of the spread of shapes/sizes, as well as avoiding measurement errors. Also make sure the chamber is really clean - a .45 caliber phosphor-bronze brush on a pistol rod can be useful for .30 caliber rifle chambers (don't get the rods with rotating handles).

Bullet Comparator

bulletcomp.jpg (66.95 KiB) Viewed 1478 times

I think I also found the reason for the neck tension problem - My error...I cleaned the inside of the necks after I'd resized them - I was using a stiff PB brush in a drill, and it may have opened the neck up a tiny bit.
...could this small difference have altered the neck tension?

As you have found, cleaning the inside of the neck after sizing can open up the necks slightly, giving varying neck tension and consequently increasing the variation in seating depth, so if you are going to clean the neck always do so before sizing it. Also, the removal of the carbon and residue from inside the neck will change how easily the bullet seats, so make sure you are consistent in this aspect of your case prep to avoid further potential sources of variation.

I aim for +/- 0.001" variation in seating depth (in fact I don't think calipers plus a comparator can reliably measure any more accurately than that anyway). I'm not particularly concerned if I see +/- 0.002" variation, but more than that and I'll look into it (I'm not a benchrest shooter however, so others are probably chasing more consistency than me) . Operating the press lever consistently is very important, and if you feel variations in resistance take that as a cue that something may have changed – at least measure that round if you aren't measuring each one. I use a non-compound press for seating, which gives better feedback than more 'powerful' presses. I would not expect to adjust the seating die once it is set up, and if you are incrementally adjusting the seating die during setup to get to your target length, don't expect to move a bullet (that you have previously seated) less than 0.002" or 0.003".

[Dougan]

Thanks very much for that Rox :)

...makes sense to measure the seating from the ogive rather than the tip. I've been following the other thread about drilling cases to measure the chamber, and was considering buying a gauge, but didn't think I'd need the comparitor that came with it - but it looks like that could be very useful aswell...apart from improving the way I measure the seating, it'll help me to sort cheep bullets (and compare them to SMKs).

It'll also mean I can measure my chambers - not so important on the .303, but I will need it when I start reloading .308...