Jam or jump - load development

[DoubleGobble00]

In load development, for seating depth, do you start out jammed for max pressure or do you start out jumping bullets? I'm tempted to jam the bullets a little (0.003) to find max pressure then jump if needed.

I was planning to loosely seat a bullet in dummy round, chamber dummy to find jam length, then back off little or start there seating depth for load development to find max pressure (working up slow). Thoughts?

DoubleG

 

[Rick Richard]

I always start jam or .010 off. I like following the Berger method.

 

[Mike 338]

For hunting, IMO, everything is "jump".

Jamming bullets in the rifling on rare occasion can act as a bullet puller if you try to cycle the cartridge out of the gun. Not only does it stick a bullet in the barrel but dumps gunpowder in the action. Not fun when your out in the middle of nowhere. If that happens at the range or a competition, you just borrow a rod from the guy next to you, push the bullet out and clean your action. Not so easy when your 50 miles from the next person your liable to see.

 

[RockyMtnMT]

After a primer failure on a hunt and watching a stud muley walk away because my bullet was stuck in the barrel and I couldn't load another round, I will never load a hunting rifle with bullets touching the lands. There is no good reason to.

 

[DoubleGobble00]

I'm having a hard time finding exact OAL since I don't have gauge. I've tried the smoke method and get Bullet to seat in brass while chambering which gives me a jammed length (lands marks on Bullet). I'm tempted to start here then back off later if needed.

I can continue to seat the bullet until no lands marks and consider this OAL. Then back off 0.01 to jump?

What is Berger method? I'm loading for a 300 Rum with 230 Berger and 300 win with 215 Bergers.

 

[RockyMtnMT]

I'm having a hard time finding exact OAL since I don't have gauge. I've tried the smoke method and get Bullet to seat in brass while chambering which gives me a jammed length (lands marks on Bullet). I'm tempted to start here then back off later if needed.

I can continue to seat the bullet until no lands marks and consider this OAL. Then back off 0.01 to jump?

What is Berger method? I'm loading for a 300 Rum with 230 Berger and 300 win with 215 Bergers.

That's how the old timers do it!

 

[DoubleGobble00]

What do you consider OAL? No lands marks on the bullet or touching?

 

[Rick Richard]

I'm having a hard time finding exact OAL since I don't have gauge. I've tried the smoke method and get Bullet to seat in brass while chambering which gives me a jammed length (lands marks on Bullet). I'm tempted to start here then back off later if needed.

I can continue to seat the bullet until no lands marks and consider this OAL. Then back off 0.01 to jump?

What is Berger method? I'm loading for a 300 Rum with 230 Berger and 300 win with 215 Bergers.

Yep. Seat it until in the lands and them take measurement. From there back off .01 and do your load development. After you have a good load, then consider the Berger method for identifying best seating depth. Berger method can be found on their website.

 

[RockyMtnMT]

What do you consider OAL? No lands marks on the bullet or touching?

No marks on the bullet.

 

[Rick Richard]

From Berger website:

Load 24 rounds at the following COAL if you are a target competition shooter who does not worry about jamming a bullet:
1. .010 into (touching) the lands (jam) 6 rounds
2. .040 off the lands (jump) 6 rounds
3. .080 off the lands (jump) 6 rounds
4. .120 off the lands (jump) 6 rounds

Load 24 rounds at the following COAL if you are a hunter (pulling a bullet out of the case with your rifling while in the field can be a hunt ending event which must be avoided) or a competition shooter who worries about pulling a bullet during a match:
1. .010 off the lands (jump) 6 rounds
2. .050 off the lands (jump) 6 rounds
3. .090 off the lands (jump) 6 rounds
4. .130 off the lands (jump) 6 rounds

Shoot 2 (separate) 3 shot groups in fair conditions to see how they group. The remarkable reality of this test is that one of these 4 COALs will outperform the other three by a considerable margin. Once you know which one of these 4 COAL shoots best then you can tweak the COAL +/- .002 or .005. Taking the time to set this test up will pay off when you find that your rifle is capable of shooting the VLD bullets very well (even at 100 yards).

 

[ar10ar15man]

big problem with JAM is it also jumps pressure...quickload says add about 7200 for starting press.
you did not say for hunting or target?
i agree no reason to JAM hunting loads.
i start all my work up AT THE LANDS, TOUCHING no jam.
clean the gun....zero copper in the throat
it takes work, polish a bullet, seat, look and marks and change seater, do it all over again. till the marks go away, then make it longer .001 at a time till you see the lands touch( it helps to have a nice clean square throat)
you are at high pressure point for your max load, anything else will be less pressure.
if you go to jam, you KNOW you have to decrease and work up.

 

[ar10ar15man]

read the fine print...their VLD bullets.
and their method sells a lot of their bullets.
48 without sighting rounds.

From Berger website:

Load 24 rounds at the following COAL if you are a target competition shooter who does not worry about jamming a bullet:
1. .010 into (touching) the lands (jam) 6 rounds
2. .040 off the lands (jump) 6 rounds
3. .080 off the lands (jump) 6 rounds
4. .120 off the lands (jump) 6 rounds

Load 24 rounds at the following COAL if you are a hunter (pulling a bullet out of the case with your rifling while in the field can be a hunt ending event which must be avoided) or a competition shooter who worries about pulling a bullet during a match:
1. .010 off the lands (jump) 6 rounds
2. .050 off the lands (jump) 6 rounds
3. .090 off the lands (jump) 6 rounds
4. .130 off the lands (jump) 6 rounds

Shoot 2 (separate) 3 shot groups in fair conditions to see how they group. The remarkable reality of this test is that one of these 4 COALs will outperform the other three by a considerable margin. Once you know which one of these 4 COAL shoots best then you can tweak the COAL +/- .002 or .005. Taking the time to set this test up will pay off when you find that your rifle is capable of shooting the VLD bullets very well (even at 100 yards).

 

[DoubleGobble00]

Yep. Seat it until in the lands and them take measurement. From there back off .01 and do your load development. After you have a good load, then consider the Berger method for identifying best seating depth. Berger method can be found on their website.

When I seat into the lands, it takes a lot more than .01 to not have lands marks. It appears to take .02 at least to get rid of lands marks. So I assume this is still slightly jammed or touching if I have marks.

 

[DoubleGobble00]

No marks on the bullet.

Thanks what I was thinking but wanted to be sure. It takes very little pressure to get lands marks.