Why Hammer Bullets Are Always Faster

[Hand Skills]

Stay humble and hungry and please keep up the good work, pushing the limits and enjoy the journey!

Amen!

 

[RockyMtnMT]

Hungry is easy. I think it is just a way of life. Humble...I think a person has to remind themselves of this. There is some people that think I am not, simply because I fight back. That has nothing to do with humility. I know that there are people that are better than I am at everything. I try to get better at whatever I am doing. We can always do better. Part of what makes a person hungry maybe. The greatest humility is knowing that we can't do this without the grace of God. I try sometimes and it never seems to work out.

 

[nugentfan]

No idea if this thing works but it's been on my wish list for a couple years.

Rifle Barrel Chamber Pressure Testing Hardware & Software | Pressure Trace

Measure ACTUAL rifle chamber pressure for each shot, barrel harmonics, rise time, time to muzzle exit and OBT barrel timing.

www.shootingsoftware.com

I am a cautious loader but have had a couple projects that were a bit awkward, .25 Gibbs for one. For the most part I have found Hammers to be faster than what I was using with cup and core.

 

[Hard rock]

No idea if this thing works but it's been on my wish list for a couple years.

Rifle Barrel Chamber Pressure Testing Hardware & Software | Pressure Trace

Measure ACTUAL rifle chamber pressure for each shot, barrel harmonics, rise time, time to muzzle exit and OBT barrel timing.

www.shootingsoftware.com

I am a cautious loader but have had a couple projects that were a bit awkward, .25 Gibbs for one. For the most part I have found Hammers to be faster than what I was using with cup and core.

I know what you mean , my first wildcat 6.5-06 never could reach the potential of that cartridge without blowing primers , etching bolt faces etc . Finally rebarreled it to a 6.5-284 20 years later and a world of difference , but the education was priceless. If I would have loaded it to P.O. ackley s data I wouldn't probably be here. I'm still scratching my head on that one.

 

[Lou270]

Even if you had pressure testing equipment , the answer would still be Yes , but you keep skirting around a simple question , so there is absolutely no answer that would put your mind at rest . Even if Hammer bullets had pressure testing equipment , there would be doubt because the data would be so far off conventional data , it would put doubt in your mind . If you loaded a Hammer bullet with a bearing surface of .5 compared too a bullet of .7 , everything else being equal including pressure the Hammer bullet would be faster , how you measure that pressure is another story.

Since a direct question I will answer. If pressure tested load data shows hammer bullets get higher velocity, yes, I would use that data. I have said this a bunch of different times.

Lou

 

[Zen Archery]

So you know. SAAMI pressure specs are not set by any kind of testing by a governing body to see where the failure of any components or rifles is with a specific cartridge. My understanding is that the designer of a cartridge will pick a number and call it the SAAMI spec. Nothing more than that is required.

100% Accurate. Built a wildcat caliber last year. When I ran data through QL I noticed developer used a PSI (pressure) number 5,000 over SAAMI parent case. When I asked him about it, his response was those SAAMI numbers are over 40 years old. He states most quality cases/brass handle much higher pressure than the 40 year standard.

 

[ButterBean]

You can model this in Quickload. You have to back into a particular bullet's engraving pressure by comparing muzzle velocities at the same powder charge between that particular bullet and the reference bullet that you used to tune your powder burn rate to match Quickload projections.

It's engraving pressure that makes all of the difference from one bullet to another of the same weight. Max chamber pressure happens in the first few inches of bullet travel. If the bullet takes higher chamber pressure (and more powder burn time) to force it fully into the rifling, it will build a lot more chamber pressure before the bullet really gets moving. So you end up with higher average pressure working on the bullet as it travels through the first few inches of barrel, and you get more muzzle velocity.

Once a bullet is fully engraved, I can't imagine drag on the bullet has much effect on muzzle velocity. But a bullet with high engraving pressure will definitely have higher muzzle velocity (and higher chamber pressure) than a bullet with low engraving pressure (at the same powder charge.)

But! The bullet with low engraving pressure can take a lot more powder to reach the same max pressure, and that extra powder keeps the pressure behind the bullet higher for the entire time it's traveling down the barrel. So the bullet with the lowest engraving pressure ends up with higher muzzle velocity when loaded to the same max pressure.

To answer your question, in my rifles I get about 100 fps higher velocity from Absolute Hammers than I get with hard-to-engrave thick-jacketed hard-lead-alloy bullets such as Nosler Partition or Sierra Tipped Game Kings. This is with the same max chamber pressure calculated by Quickload with powder burn rate and bullet starting pressure tuned to reflect range data.

You may be surprised how small this Absolute Hammer advantage is in my rifles. Some folks claim that they get 300 fps higher velocity with Absolute Hammers. The reason I only get 100 fps is that I don't load up to sticky bolt lift. I work up loads using ejector print on soft-headed Nosler or Norma cases, with Quickload (tuned to a published Hodgdon powder charge, bullet type, and chamber pressure) as an extrapolation tool.

My own view is that sticky bolt lift is not a reliable indicator of safe working pressure limit. For example, given the tenon diameter in my rifles I estimate that a standard-diameter case (e.g. 30-06) will take 30% more pressure to hit sticky bolt lift than does an ultra-magnum diameter (e.g. 28 Nosler) case. That may be why the folks claiming the highest increase in muzzle velocity for Absolute Hammers are the folks shooting standard-diameter cases. But they may be running VERY high pressure to get that uplift.

Entirely to much work for me when I can have a load worked up in 5 shots and be shooting

 

[RockyMtnMT]

Since a direct question I will answer. If pressure tested load data shows hammer bullets get higher velocity, yes, I would use that data. I have said this a bunch of different times.

Lou

What if it was too hot for your rifle? How would you ever know?

 

[adam32+P]

What if it was too hot for your rifle? How would you ever know?

Just a question, but is it mainly the rounded drive bands that you contribute as the biggest factor for higher velocities?

Do GS Custom or Peregrine bullets also achieve higher velocities?

Do you know other bullets with comparable bearing surface like the Absolute Hammers?

I agree that bullets with less bearing surface (slipperyer) should be/are faster at equal pressures.

 

[RockyMtnMT]

Just a question, but is it mainly the rounded drive bands that you contribute as the biggest factor for higher velocities?

Do GS Custom or Peregrine bullets also achieve higher velocities?

Do you know other bullets with comparable bearing surface like the Absolute Hammers?

I agree that bullets with less bearing surface (slipperyer) should be/are faster at equal pressures.

Yes. Drive band designed bullets will generally show lower engraving pressure. I have never shot a peregrine bullet. I have shot a lot of gs bullets. Gs bullets are capable of generating higher velocities for their weight. Different designed drive bands but similar in concept.

 

[Lou270]

What if it was too hot for your rifle? How would you ever know?

I made a post on using pressure tested data/velocity already so you can look back.

In any case I am not sure what that has to do with whether a certain bullet can reach higher velocity or not (assuming same max pressure) and certainly not by how much. My methods nor any of the other folks have presented can tell you that.

Lou

 

[RockyMtnMT]

I made a post on using pressure tested data/velocity already so you can look back.

In any case I am not sure what that has to do with whether a certain bullet can reach higher velocity or not (assuming same max pressure) and certainly not by how much. My methods nor any of the other folks have presented can tell you that.

Lou

No problem Lou. I'm just picking on you. The good thing is you don't get mad.

I may have missed it. Did you answer my food for thought statements last night? Is it simply weight of a bullet that dictates velocity or is potential velocity effected by design?

 

[Lou270]

No problem Lou. I'm just picking on you. The good thing is you don't get mad.

I may have missed it. Did you answer my food for thought statements last night? Is it simply weight of a bullet that dictates velocity or is potential velocity effected by design?

I think I missed it. Design impacts velocity, not just weight. Other things affect velocity but related to bullet the things I can think of that impacts velocity is engraving pressure and projectile length (ie reducing powder space).

Engraving pressure is dictated by distance to lands, bearing surface, bullet construction, materials, type and dimensions of rifling, and probably something not thinking of.

Engraving or shot start pressure basically influences how fast reach top pressure for a given load. If lower EP from one bullet to next you can add some powder back to reach same max pressure and could gain some extra area under the p/t curve for more velocity depending on burn rate of powder as rise slope will be little less steep

Lou

 

[Hard rock]

I think I missed it. Design impacts velocity, not just weight. Other things affect velocity but related to bullet the things I can think of that impacts velocity is engraving pressure and projectile length (ie reducing powder space).

Engraving pressure is dictated by distance to lands, bearing surface, bullet construction, materials, type and dimensions of rifling, and probably something not thinking of.

Engraving or shot start pressure basically influences how fast reach top pressure for a given load. If lower EP from one bullet to next you can add some powder back to reach same max pressure and could gain some extra area under the p/t curve for more velocity depending on burn rate of powder as rise slope will be little less steep

Lou

I'm not sure I'm comprehending this statement , but it sounds like you are starting to get it, maybe I'm wrong. Bottom line with Hammers you always wind up achieving higher velocities, taking everything in consideration you stated when working too a max load.