303 Epps reloading data ?

[Treeman]

@Treeman. What speed from what charge?

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Its hard to say, because the cases seem to be at various stages of fireform. It seems that if there is any forming still to happen it drastically changes velocity. I have had cases with full 1 grain more charge show lower velocity than the one grain lower charge case.

[Treeman]

I even started doubting my chroni.

new batteries first use.
46.3 gr -2438
47.3 gr 2520
47.7 gr 2448
48.8 gr 2506

So is the 46.3 -47.7 - 48.8 correct and the 47.3 the false reading, or 47.7 the odd reading . I am assuming that energy is being lost due to case expansion still happening.
Problem is 47.3 was touching holes and 48.8 2 touching one a bit off.
Are the cases odd because of annealing ?
Is it the not yet formed cases ?
Am i just a dick ?

[Tripodmvr]

I even started doubting my chroni.

new batteries first use.
46.3 gr -2438
47.3 gr 2520
47.7 gr 2448
48.8 gr 2506

So is the 46.3 -47.7 - 48.8 correct and the 47.3 the false reading, or 47.7 the odd reading . I am assuming that energy is being lost due to case expansion still happening.
Problem is 47.3 was touching holes and 48.8 2 touching one a bit off.
Are the cases odd because of annealing ?
Is it the not yet formed cases ?
Am i just a dick ?

What are you saying - different COL?

[janfred]

Did you fir the rounds on the same day? 3 shot groups, five shot groups?

[Treeman]

What are you saying - different COL?
[/quote]
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The cases do not, have not yet fully formed to the chamber, so COL is correct, but the shoulder is sometimes still rounded or the walls not yet expanded fully.

[Treeman]

Did you fir the rounds on the same day? 3 shot groups, five shot groups?

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Yes on many days, mostly 4 shot groups. About a 100 attempts.

LATEST>  It appears the reamer used is not on spec. The fired cases are too fat to even fit in a full length sizing die, I am stopping everything now and waiting on gunsmith investigation.

[Bushbuck]

Good day to all, and may 2025 hold all that is dear to you.

I am reverting to the original question and just giving my end results and some background and with experiences.

1)    I have not attempted to become a long range BR shooter.  I have an old target with grouping from 174 gr PMP cartridges and if I do better than that I'm happy I'm on the right path.

2)     My 303EPPS is a P14 action, has a water capacity of 63,2 gr and barrel length of 26"
 
3)    Try as I may, I have never been able to find a load for core bonded bullets 150, 180 and 200 gr.  Sometimes I didn't get all 4 bullets on an A4 target
 
4)   Thus far, I have only used Somchem powders.

5)   My fire form load is 45 gr S341 with Hornady 150 gr SP.  The grouping is good enough for hunting out to 150 m on warthogs where I'm regularly not going for head shots.  The Hornady 150 gr SP gave the least cartridge splits.

6)   Hornady 150 gr SP is loaded with S335 at either 45,0 gr or 46,9 gr

7)   Hornady 174 RN is loaded with 49,7 gr S365 and is the best load I have.  At 100 m I get groupings under 1".

[Ds J]

What does she do with regular milsurp, or with FMJ bullets?

[Bushbuck]

I don't know.  I've never had any milsurp and since I have never intended to hunt with FMJ, never bought any FMJ heads.

[Ds J]

If it does not even group with FMJ, the fault is probably something else. I don't understand how/why regular cup and core bullets work, but bonded bullets dont. Maybe it has to do with the balance of the bullets? Very unusual indeed.

Is it original, with just the chamber reamed, or with a new barrel? 

In many cases, grouping troubles has to do with a shot out barrel, or certain bullet weights, or certain bullet designs.

[Treeman]

The bore is loose, oversize and therefore bonded bullets being harder bed worse than softer cup and core bullets.

[Bushbuck]

The rifle was rebarrelled by Truvelo and Bloemfontein Rifles did the reaming of 303EPPS.  I have not kept shot count but will safely say it's under 1000 rounds.  When I collected the rifle from Truvelo, I specifically asked the bore diameter and the gunsmith said it was "X" mm (don't remember the figure) according to SAAMI standards, which converted to 0,314.  I've never had a gunsmith confirm.

[Ds J]

With 0.314" diameter,  the bore is very loose indeed. Have you considered custom turned bullets?

A very experienced gun smith once told me that undersized bullets increase barrel wear.

At least you know the source of the trouble!

I have heard that Kriek bullets has done custom work.

[big5ifty]

Make your own custom bullets, cheap and easy.

Cast .308 paper patched goes to .314 very nicely.

220 grain Lee mould is cheap.

[Treeman]

Find someone like Kriek to make you 60 test rounds and if you get them shooting true ask for a price on like 500. You and that rifle sorted for your life at least.