Hmm.. help me make sense of this.

snowstorm

Well-Known Member
Have a look at this photo of some shell cases I fired yesterday.

http://www.thestalkingdirectory.co.uk/trophy-room/showphoto.php?photo=334&cat=500

The loads are increasing from 39gr to 39.5 gr left to right, there are 6 rows 0.1 gr increments, running diagonally bottom left to top right.

Row 6 - 39.5 is getting close to the maximum 0f 40.3 gr (VV data) and I'm not going any higher.

Look at the powder marks on the shoulders increasing as the load increases.

I had low pressure signs down at 35 grains and they gradually decreased as I passed 38.5. I thought they would go completely as I passed 39 not come back.

So, is this also a high pressure sign? There are no pressure signs/marks on the heads. Bear in mind the rifle at this point is probably getting quite dirty inside.

Your thoughts appreciated.

243, 87 grain head, winchester brass and primers. VV N140.

Cases are all fired once and neck resized.
 

Bob

Well-Known Member
I assume you haven't had this problem before.

If you haven't cleaned the rifle try some other known loads including factory loads both in same and different brass which normally do not exhibt this problem to see if same effect. If so you get the same problem then fault probably lies with the rifle/cleaning.

Clean rifle or start with a clean rifle and try loads again. By a process of elimination you should be able to narrow the field and identify the problem.

If you have to load more to test weigh each load and carefully check all components for contamination. If you have some left pull a few and check all is ok.

If you have access to a chronograph use this when testing loads as it will give valuable information as to how your loads are performing in comparison to each other and to factory loads.

Don't attempt the following if you are clumsy, hamfisted don't pay attention to detail or are unlucky, if you are give up reloading now!

Primers from different batches can be roughly assessed by loading a few of each batch into empty cases, going to a safe location loading them one at a time and firing preferably in a dark location so you can compare the bang and the flash. Probably not a reccomended proceedure and you do it at your own risk and responsibility. Its interesting and gives a subjective comparison but not an accurate one. For purposes of elimination only.

Different Heath Robinson tests can be tried for powder again at your own risk. Use an A4 size piece of plywood or hardboard -outside, not in the house!- and make some lines of powders you wish to compare about a pencil length and thickness. Set a match to them and compare burning speeds! Be careful and be very careful if trying out black powder as it goes very quickly. Make sure all powder containers are closed and well away from the test area before lighting the powder trails. It has'nt altered my ability to type but then I only use two fingers anyway. Really not too dangerous and if you think about it The Customs officers used to test for proof in distilled alchol by mixing black powder and the distillate and setting a spark to it. if it flashed then it was proof alcohol, if not it wans't. The proof testers were hand held I believe as were flint lock pistols where the priming powder was held outside the barrel in the flash pan.

Have fun and I'm sure you will sort out your problem quickly!

Bob
 

300wsm

Well-Known Member
What are you using to neck size and what is the neck tension like?

I have to say that obturation looks poor on most of the cases regardless of powder charge.

I would look at either getting at factory crimp die or a die that you can increase the neck tension on.
 

snowstorm

Well-Known Member
Thanks both,

I know, it's a lot and wasn't expected. The residue is very evident at 34 then minimises at 38-39, then increases again.

I'm not sure how to quantitatively measure neck tension, but it takes a fair bit of pulling to get the heads out. I need leverage from the press to do it.

I'm using the Lee neck resizing die, I also have a Lee crimp die but most things I read say not to use it. I'm worried this might be a high pressure sign and I don't want to do anything to increase the pressure any more.

One thing that did catch my attention - the instructions for the neck resizing die said a lot of effort is needed at the end of the stroke to resize - I did not have to exert a lot of effort to use it, and I'm sure I had it set correctly.
 

ReneZ

Well-Known Member
You'll want to be carefull as the bullets you are using are not meant to be crimped, they don't have a cannelure.
Was it difficult to open the bolt?
 

ReneZ

Well-Known Member
S.
No, not to my knowledge/experience. Excessive pressure forms the case to the chamber/headspace and will always seal well by expansion, what doesn't seem to have happened in your case. Even if the rifle was still dirty from earlier low pressure rounds the progressive loads would have sealed and cleaned it out eventually, but it seems that de higher loaded ones created stronger low pressure signes. In that case it would almost be as if the bullet was loose in the brass and was rambling through the bore, preventing proper pressure build-up.
Sorry, no straight forward answer here.

Rene
 

snowstorm

Well-Known Member
Yes, it's the same rifle. That's why this is unexpected, I tried to control all the variables except the powder load.

The brass was all new from the same batch, and the primers from the same batch of 1000. The heads were from the same box.

The only thing suggested to me is that my scales are out, I will test them tonight with a selection of heads to see how accurate they are.

Another confusing thing is that within each load there is such a variation in how much residue there is.

Edit : tested scales, they are spot on.

Also : depending on where I read the powder charge for this head starts at 29.6 gr and goes up to a max 40.1 gr. You can see why I'm struggling to see a 39.5 gr load as producing low pressure?
 

snowstorm

Well-Known Member
Muir said:
Crimp (a Lee Factory Crimp Die does not require a cannelure) and if not, switch to a faster powder like 4895. ~Muir

Thaks Muir, it sounds like a plan. I have a Lee Crimping Die, but didn't use it because the Lee site says not to crimp hunting loads.

Do you hny idea why they say that?

S.
 

Richard Parsons

Well-Known Member
The leaflet says you need 25 lbs of squeeze on the sizing die to get neck tension. Works for me in .308 and .223 but .243 does seem very loose and I sometimes crimp lightly for peace of mind......... odd.

ATB
 

Muir

Well-Known Member
snowstorm said:
Muir said:
Crimp (a Lee Factory Crimp Die does not require a cannelure) and if not, switch to a faster powder like 4895. ~Muir

Thaks Muir, it sounds like a plan. I have a Lee Crimping Die, but didn't use it because the Lee site says not to crimp hunting loads.

Do you hny idea why they say that?

S.

Actually, it says that Neck Sized cases aren't recommended for hunting. Of crimping there is no mention. After all, isn't that where you'd want a crimp? I use them all the time in the field.~Muir
 

snowstorm

Well-Known Member
Muir said:
Crimp (a Lee Factory Crimp Die does not require a cannelure) and if not, switch to a faster powder like 4895. ~Muir

Muir, when you crimp do you do it the maximum or just lightly ?

I tried an empty case in the Lee die today and it compressed it a heck of a lot before the collet finally closed.

S.
 

Muir

Well-Known Member
Snow: The collet doesn't need to close completely; in fact, it shouldn't. About half closure is good enough for most of what I do. I do it by feel, initially. Then move in 1/4 turn until I reach the best crimp. This may take a series of reloadings. The main thing for me is that the crimp be consistent -which requires uniform case length and if possible, same LOT brass. In many cases, any crimp will aid to the uniformity of neck tension ("pull weight) on the bullet. I may have mentioned that my Hornet was shooting 7/8" at 100 yards before I crimped. Then it would consistently mark a half inch. IMHO, Any time you have inconsistent brass (a description which suits Winchester Hornet brass quite well!) a crimp will aid in accuracy. ~Muir
 

snowstorm

Well-Known Member
Thanks, so do you, for instance, screw in the die until it touches the shell holder then back it off 1/4 or 1/2/ a turn? Or do you leave it and press the lever by the same amount each time?

I'm hoping that I can start again at the lower end of the powder wieghts and lose some of the low pressure signs.

S.
 

buck52

Well-Known Member
Seems to me to need more neck tension, personaly I would adjust the dies rather than crimping.

If you are using a lee collet die take out the mandril, put it in an electric drill and finely polish the shaft with very fine wet & dry, this should give you a little more neck tension.
 

snowstorm

Well-Known Member
That's my final option.

I fired some neck sized rounds las weekend going back down to a lower load and things looked better, I'm going to try a slightly heavier load next and if that doesn't do the trick I'll get going on the mandrel.

Cheers,

S.
 

mack

Well-Known Member
crimp

Hi, crimping is not neccesary unless you are using a tubular magazine or a heavy recoiling round, something like a .338 and above.
 

Muir

Well-Known Member
Re: crimp

mack said:
Hi, crimping is not neccesary unless you are using a tubular magazine or a heavy recoiling round, something like a .338 and above.

With all due respect, your statement is not accurate. That aside, though, the issue should be a question of whether or not crimping is beneficial, not necessary.~Muir
 
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