Thread: Pressure / barrel speeds?

Originally Posted by Gibo

Nasty

Had a beer or two after that one

Originally Posted by veitnamcam

Fixed

hahaha

federal all the way brother

Originally Posted by BRADS

Had a beer or two after that one

I bet. Good tip on the handloads given with sale. Pull em or chuck em

Originally Posted by Gibo

I bet. Good tip on the handloads given with sale. Pull em or chuck em

Take you don't want 90 22-250 loads?
Warmish lol

Originally Posted by Gibo

Ok guys im trying to get my head around a few things.

Firstly pressure. Why is it lighter pills in the same cal can use more of the same powder than heavier pills. Is it to do with resistance?
How can this effect the case differently (pressure wise) ?

Secondly barrel speed?? If someone has told me my barrel is slow (tikka) how could a magnum of same cal same (tikka) go any faster?

Just getting my head around the basics of reloading so keen to learn. Hope these even make sense: D

1-The lighter pill gives less resistance to the explosive charge trying to move it, the charge is able to expand into the increased space as the lighter projectile is driven out of it's (the gas) way faster than a heavy one - the heavier projectile has more inertia for the gas to overcome before it can drive the projectile down the bore to relieve pressure by creating space (volume), so if the heavier charge is the same as the light charge, pressure spikes faster because it has nowhere to go. When the resistance is too great, the pressure will find somewhere other than the bore to go, like back through the primer and bolt vent.

2-Two barrels from the same manufacturing run, in the same length, twist rate and calibre will not (near impossible in mass production ) be identical in bore dimension, as the projectile swages to the bore, so it is gripped and rotated, the tiniest, microscopic difference in the bore dimensions will change the resistance level to the projectile, the one with greater resistance will be the slower of the two.

So in order to build a "fast barrel" one would want the minimum possible land hight and width while still managing to turn the projectile?

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No one has mentioned type of rifling or projectile bearing surface?

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Originally Posted by R93

No one has mentioned type of rifling or projectile bearing surface?

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Do tell?

Originally Posted by Gibo

Do tell?

Someone will no the proper answer but this is my basic understanding.
Some of the longer double banded (Barnes pills?)create way more pressure than the same weight in other pills,
Has caught a few out

Here's a few pictures and details of what was bad. There was some good from this one though.................. the chamber didn't explode in my face! This had very, very high pressure.

This was/still is a 223 MAX in Remington Model 700 - 60gr Partition doing 3640fps in a 1:12 twist factory barrel. The chamber has been reamed deeper to allow the extra length and powder capacity. 31.5gr of 2206H (my current safe load is 30.5gr giving 3420fps)

This photo show the ejector pin mark(the half moon or simile mark) on the side of the base. this is from when the brass flows so much that the pressure is enough to push the ejector pin back into the bolt. Sometime this can just look like a polished half circle in the base.
Also in this picture the primmer pocket has expanded so much that the primmer fell out. Lastly you can see scratches on the case; these are from the case has expanded so much that any tooling marks from the chamber reamer has allowed the brass to fill the marks and therefore mark the case very, very hard to extract. Again, this is a pretty extreme case of high pressure.


This one shows how much of the case is out of the chamber. This is not meant to be a belted case.

Shit! Thanks for that

Backed off half a grain and called it good?

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If given loaded rounds if you

1. Put one in the gun and bolt closed smoothly
2. Had a modded case and checked length then measured the reloads OAL
3. Had some of his used brass to visually check plus see how that went into the gun
4. Pulled one projectile and weighed the contents. Compared to the books.

After all of the above you d surely have to be ok ? And comfortable to pull the trigger on a couple of them ?
The .243 I m trying to sell for example can have to the right person 51 x brass 2 x fired plus there is 42 90 Gr Targex loads that are awesome..
To throw them away would be dumb. To reload them would be dumb. They are all set to measured length etc For me to keep them would be dumb !

If YOU were to buy this gun would you not use them ?

Originally Posted by Happy

If given loaded rounds if you

1. Put one in the gun and bolt closed smoothly
2. Had a modded case and checked length then measured the reloads OAL
3. Had some of his used brass to visually check plus see how that went into the gun
4. Pulled one projectile and weighed the contents. Compared to the books.

After all of the above you d surely have to be ok ? And comfortable to pull the trigger on a couple of them ?
The .243 I m trying to sell for example can have to the right person 51 x brass 2 x fired plus there is 42 90 Gr Targex loads that are awesome..
To throw them away would be dumb. To reload them would be dumb. They are all set to measured length etc For me to keep them would be dumb !

If YOU were to buy this gun would you not use them ?

I wouldn't now
In the past yes....my life is worth more than that two me
3 grains of powder two much in a small case like a 22-250 = no fun.
Not helped buy the particular power BM2.
I did all of the above before using the reloads......but it only takes one

Originally Posted by BRADS

I wouldn't now
In the past yes....my life is worth more than that two me
3 grains of powder two much in a small case like a 22-250 = no fun.
Not helped buy the particular power BM2.
I did all of the above before using the reloads......but it only takes one

Sorry Brads I m confused now ,,, If Im right you saying just the one was over the safety mark. Yes agree you could get caught out.


so did you pull and weigh one of the loads and it was ok within limits.. or ???

Inattentive reloading could be dangerous for sure. Our machine has so far never had a fail or over beep. We check it and recheck it during the process but others may not for sure.