Reduced loads of slow powders and SEE with cast?

[andym79]

Hi guys, whats the likelihood of experiencing a SEE when using a reduced load of a slow powder and a cast bullet!

It seems from what I have read CB will not get stuck and result in a pressure spike! I am however still uneasy about loading up with a slow power in reduced loads!

Also can a reduced load of H4831 really produce the same velocity in a CB with 12 grains less than it takes to get a jacketed one there?

There really insn't much published data at all for slow powders and CBs!

I should outline what I mean by reduced load. The max load for H4350 and H4831 are 44 and 47 respectively! I am looking at loads of 30-33 and 35-38 respectively in the 6.5X55.

 

[USSR]

whats the likelihood of experiencing a SEE when using a reduced load of a slow powder and a cast bullet!

Somewhere south of zero. I'm presently working on a cast bullet load for a 247gr cast bullet in the .30-06. I started with 18 - 20gr of IMR4227, and am now working with IMR4895 loads with 22 - 24gr of powder. Will at some point try < 30gr of RL22. Am using 0.75gr of dacron fill to keep the powder at the case base. I am using PB bullets and looking for a velocity in the neighborhood of 1400-1500fps. With the amount of powder you are talking about using, you sure better be using a gas checked bullet.

Don

 

[andym79]

So if a SEE is possible when using cast. The best way to avoid it is good neck tension and a firm crimp?

Further still to make this unlikely event, even more unlikely a 160 grainer in the Swede touching the rifle from the start?

 

[USSR]

So if a SEE is possible when using cast. The best way to avoid it is good neck tension and a firm crimp?

When I said "Somewhere south of zero", that means it is not a concern. Cast bullet loads are an entirely different animal from jacketed bullet loads. As for neck tension, cast bullet loads typically use light neck tension so as not to reduce bullet diameter, and you only need enough of a crimp to ensure that you don't stick a bullet in the throat should you decide to remove a round from the chamber without firing it.

Don

 

[rcmodel]

I agree.

SEE, so far as I know, has been confined to over-bore Magnum calibers, using reduced loads of slow burning powder.
With jacketed bullets.

Your 6.5x55 with lead bullets fits none of those requirements.

On the other hand?

Reducing H4831 to lead bullet velocity levels is about as bad an idea as I can think of.

Use the proper powder you can find lead bullet data for.
And Bee Safe & Happy!

rc

 

[andym79]

Reducing H4831 to lead bullet velocity levels is about as bad an idea as I can think of.

I am not say that you are wrong not by a long shot! I am trying to find an accurate high velocity load using cast bullets in the 6.5x55. I have got up to 2000fps with H4895! I am going to start testing using Varget.

I wondered however if I want to hit 2300fps whilst retaining accuracy that I might need to give the bullet a softer push, slower acceleration. I suspect only H4350 or H4831 could achieve that.

 

[andym79]

On a slightly off topic Lees manual lists a lot of reduced loads for the 30-06 whilst not similar in its over bore characteristic of the 6.5x55 is serves to demonstrate that loading down even of slow powder can be done, depending on the projectile weight to bore ratio!

For example Lee lists reduced loads of Varget down to as low as 26 grains in the small for bore 130GN projectile. (For jacketed its 49+)

H4350 is first listed for the medium to bore projectile of 165GN and goes as low as 29 grains. (For jacketed its 51.8+)

H4831 is first mentioned at the medium-heavy for bore 180GN projectile, but it does go down as low as 29 grains and list a low 15000psi. (For jacketed its 51.8+)

The super slow H1000 is first mentioned at a heavy for bore 200GN projectile and goes down as low as 39 grains. (For jacketed its not listed)

On that principle then in the 6.5x55, Varget is suitable for all but the smallest projectiles. H4350 should be suitable from 129 grains upward, H4831 for 140 grains upward and H1000 only for the biggest projectiles 160GN +.

Lee suggests
"The slowest burning powder should not be reduced more than
20%. Each preceding powder may be reduced 1% more.
Example: 20%, 21%, 22%, 23%, 24%, etc."

If I apply this principle to the 6.5x55, and only to Hodgdon (ADI) powders due to availability.

For a 139-144GN projectile.
H870 - 20% (53x.8=42.4)
H1000 - 21%(50x.79=39.5)
H4831 - 22% (47x.78=36.7)
H4350 - 23% (44x.77=33.9)
Varget - 26% (36x.74=26.6)
H4895 - 27% (35.8x.73=26)

These figures of course would relate to a hypothetical load without a filler and in theory with a filler to reduce case capacity could probably be a bit lower.

 

[USSR]

Lee suggests
"The slowest burning powder should not be reduced more than
20%. Each preceding powder may be reduced 1% more.
Example: 20%, 21%, 22%, 23%, 24%, etc."

This applies to jacketed bullet loads, but not to cast bullet load. As previously stated, 2 entirely different animals.

Don