Absolute Hammer actual vs Quick-load

[Mike D Texas]

Yup.

So is Hammer working with QL to resolve the said issues?

 

[Mike D Texas]

In my (limited) experience using QL and then shooting load ladders to find pressure.....I see pressure signs starting at about 1.5% to 2% below what QL says is max pressure.

Example, if QL says cartridge X using 50.0gr of powder P under Hammer bullet H gives me 61,999psi (1 psi below SAAMI spec for X), I would expect to find pressure starting at 49.0gr at the range.

Thursday I was testing a Savage Lightweight model 11 in 6.5CM using 85gr Hammer Hunters. Nosler brass, WLR primers, W748, 2.603" OAL. QL says 45.5gr should give me 62,737psi against a spec of 63,091psi max. One more tenth of powder and QL says it will be over the max psi. I should have known better, but I started my ladder at 44.0gr just for sighters and cleaning rounds. Here is the results of my range day last Thursday:

44.0gr 3 shots, 3402fps average. 0.49" group. 24.83 SD
44.5gr 3 shots, 3413fps average. 0.88" group. 7.57 SD. Slightly sticky bolt, hard to extract
45.0gr 1 shot, 3433fps. Blew the primer! 0.004" head growth! Bolt hard to lift. Very difficult to extract.

So, right on time, the pressure signs started at 2% under what QL said was max. I've been noticing, in my very limited experiences with QL and Hammers, that the 2% seems to be a good point of reference for max load......and then start reduced well below that number. The general rule of thumb to reduce 10% and work your way up seems to be good advice IMHO.

What I have found is the Hammers, especially the Absolutes work with a very narrow set of powders.
Sometimes when I get it right with powder selection the Absolutes run very close to what QL predicts. If I pick wrong the velocity suffers or they pressure out very quickly. It's pretty frustrating to burn components trying to find that one powder they like.

 

[choprzrul]

What I have found is the Hammers, especially the Absolutes work with a very narrow set of powders.
Sometimes when I get it right with powder selection the Absolutes run very close to what QL predicts. If I pick wrong the velocity suffers or they pressure out very quickly. It's pretty frustrating to burn components trying to find that one powder they like.

Oh yes, you are 110% correct there.

A previous attempt i tried with a youth 6.5cm and those 85gr HH using Norma N202 powder was a real failure. Sticky bolt at 3050fps....

 

[Carey Farmer]

Carey Farmer[/USER] Do you have any reason to go so far off the suggested SSP's? Especially when the nominal with Hammers drops to like 2200psi? Have you tried correlating with the Hammer folks or with bolt lift/case signs? I find the bolt tells a pretty good story, except with straight wall. I'm not

telling you what to do, just wondering if there is something for me to learn here.

When I get a new barrel, after twenty break-in shots in the barrel, I calibrate QuickLoad Ba and weighting factor for the powder I plan to use. That is, I shoot a few different charge weights with a light-jacketed cup-and-core bullet, and back into a Ba and weighting factor that gives the best fit for charge weight vs muzzle velocity. I use the default starting pressure (3625 psi) for that calibration. Usually only small Ba changes, and no weighting factor changes, are needed to match Quickload predictions with measured muzzle velocities.

When the loads "speed up" (and they always do in my cut-rifled barrels), the only user-adjustable parameter that makes sense (to me) to change, to match QL to the higher muzzle velocity, is starting pressure. The powder hasn't changed. The weighting factor shouldn't change. The only thing that's changed is the condition of the bore. In particular the rifling is getting heat damaged and the lands are starting to retreat. Makes sense to me that a rough, burned surface of the rifling at the lands would increase starting pressure.

What I typically find is that after the barrel has sped up, and the lands have retreated 5 or 10 thousandths, for QL to match muzzle velocity (with new-barrel calibrated Ba and weighting factor) I have to use start pressures of 8000 - 9000 psi for thin-jacketed cup-and-core bullets (eg, ELD-X); 12000 - 13000 psi for heavy-jacketed hunting bullets (Accubond or Sierra TGK's); and even higher, up to 15,000 psi for Partition or Barnes bullets. I was pleasantly surprised to see that the Absolute Hammers only needed 10,000 psi starting pressure.

I don't know if those really are the starting pressures needed to get the bullets engraved. It could very well be that new-barrel starting pressures in cut-rifle barrels are actually below the defaults, and I should be calibrating Ba with lower starting pressures than the 3625 psi I use for thin-jacketed cup-and-core bullets.

 

[Zen Archery]

What I have found is the Hammers, especially the Absolutes work with a very narrow set of powders.
Sometimes when I get it right with powder selection the Absolutes run very close to what QL predicts. If I pick wrong the velocity suffers or they pressure out very quickly. It's pretty frustrating to burn components trying to find that one powder they like.

Agreed. Absolutes are an interesting beast. I had quite a few bullets loaded before getting my hands on QL.

I reverse engineered the data just to see what was happening. Most Hammer bullets come within 100 FPS if "ALL" the input variables are corrected. And do the BA adjustment to get it 100% accurate.

When I reverse engineered Absolutes max PSI was way over SAAMI #'s. Velocities constantly 250 off. I don't worry about QL velocities but that's when I determined WF and and starting pressure was wrong.