Help tightening up Hammer groups

[QuietTexan]

The bullet is the expander if the neck wasn't expanded by a die or a mandrel before seating the bullet.

Yup.

If that is true why does your velocity go up when you have more neck tension? I'm not arguing I am purely stating what I have found after 40 years of reloading and competition. I have seen loads that acted perfectly fine without a crimp then after adding a crimp and only a crimp blow a primer. That tells me that the same load spiked in pressure magically...

Crimp =/= neck tension, they're two different things. Neck tension plateaus at the point the neck starts yielding. Crimping is mechanically deforming the neck permanently the opposite way, and requires work to overcome, hence your in-case pressure spike to pierce a primer.

Velocity will increase to a point then stop increasing because there's no tighter the neck can grip. With a crimp die you can keep increasing pressure until you make the chamber a bomb by deforming the billet with the crimp.

 

[Priley]

Not to take away from what ButterBean has already stated but here is another way to think about it...

The bullet is the expander if the neck wasn't expanded by a die or a mandrel before seating the bullet.

Try pulling a bullet from a loaded round and measure the neck ID with mandrels or something with equal accuracy. I think you'll find regardless of how undersized the neck was before seating your bullet, the neck will now measure about .001 to .003" under bullet diameter depending on how many firings the brass has seen since it's been annealed.

Yup.


Crimp =/= neck tension, they're two different things. Neck tension plateaus at the point the neck starts yielding. Crimping is mechanically deforming the neck permanently the opposite way, and requires work to overcome, hence your in-case pressure spike to pierce a primer.

Velocity will increase to a point then stop increasing because there's no tighter the neck can grip. With a crimp die you can keep increasing pressure until you make the chamber a bomb by deforming the billet with the crimp.

Agreed....

 

[milboltnut]

If that is true why does your velocity go up when you have more neck tension? I'm not arguing I am purely stating what I have found after 40 years of reloading and competition. I have seen loads that acted perfectly fine without a crimp then after adding a crimp and only a crimp blow a primer. That tells me that the same load spiked in pressure magically...

then it was over crimped

 

[ButterBean]

then it was over crimped

I'm glad you said it and thank you , I've grown tiered of explaining this over the years

 

[ButterBean]

Yup.


Crimp =/= neck tension, they're two different things. Neck tension plateaus at the point the neck starts yielding. Crimping is mechanically deforming the neck permanently the opposite way, and requires work to overcome, hence your in-case pressure spike to pierce a primer.

Velocity will increase to a point then stop increasing because there's no tighter the neck can grip. With a crimp die you can keep increasing pressure until you make the chamber a bomb by deforming the billet with the crimp.

Thank you as well my friend as I've lost the desire to explain this to the seasoned professionals

 

[SouthLoganCountyShooter]

I know when I talked with Brian. He told me 20 thousands off lands to start with. I have 3 rifles that love the 20k depth. I have one that I just couldn't get to group better than 1-1.25". Tried seating depths 10-30k off lands. Then start thinking about it. I run barnes lrx in this rifle. They liked 75k off lands best. I said the hell with it down to 5 bullets. Loaded them all at 75k off lands and bam sub 3/4moa 5 shots.

Play with seating depth. If the bergers like jump try more jump.

 

[Varmint Hunter]

I know when I talked with Brian. He told me 20 thousands off lands to start with. I have 3 rifles that love the 20k depth. I have one that I just couldn't get to group better than 1-1.25". Tried seating depths 10-30k off lands. Then start thinking about it. I run barnes lrx in this rifle. They liked 75k off lands best. I said the hell with it down to 5 bullets. Loaded them all at 75k off lands and bam sub 3/4moa 5 shots.

Play with seating depth. If the bergers like jump try more jump.

I shoot most of my Hammers at close to .100" off and have had good results. Barrels don't have just one accuracy node; they generally have several.

 

[ButterBean]

I know when I talked with Brian. He told me 20 thousands off lands to start with. I have 3 rifles that love the 20k depth. I have one that I just couldn't get to group better than 1-1.25". Tried seating depths 10-30k off lands. Then start thinking about it. I run barnes lrx in this rifle. They liked 75k off lands best. I said the hell with it down to 5 bullets. Loaded them all at 75k off lands and bam sub 3/4moa 5 shots.

Play with seating depth. If the bergers like jump try more jump.

I do just the opposite, I seat as deep as I can to start with but i don't think that is the OP's problem

 

[SouthLoganCountyShooter]

I shoot most of my Hammers at close to .100" off and have had good results. Barrels don't have just one accuracy node; they generally have several.

I understand that. I was going buy what Brian at hammer bullets told me.

 

[SouthLoganCountyShooter]

I do just the opposite, I seat as deep as I can to start with but i don't think that is the OP's problem

Got ya. I know your I just went off what Brian at hammer told me. Your definitely one of the guys to listen to on the hammer bullets. I'm new to them. Only been shooting them about 7 months. I absolutely love them.

 

[LongWalker]

Well got back out today and it was some combination of wind and crimp that gave me much better results. Two of three groups same charge weight as last time, almost the same seating depth (.005 further) and crimp were .75 MOA with the third having a weird flyer. That may have been the rifle getting a bit too fouled.

Thanks to ButterBean and all the other advice. It looks like the load will settle around 3225 fps which is as good as I would have hoped.