Absolute Hammer actual vs Quick-load

[LongWalker]

Finally picked up Quickload software a few weeks ago and have been running some of my current loads through it to compare what QL says versus the actual chrono data. The most interesting and biggest variation was with the 151 Absolute Hammer in my 30-06.

Plugged in case volume I measured which is 70.66 gr of H2O (Lapua 2x fired neck sized), 62.0 gr VV N-550 and a COL with the 151 AH of 3.255.
Rifle is a factory Franchi momentum with a 22" barrel.

QL shows slightly over SAMMI chamber pressure (62926) with a velocity of 3037 fps. My actual/observed velocity measured with my most recent three shot group (load has sped up a little) over a Magneto Speed V3 averages 3248 with an ES of 8 and an SD of 5.6. No signs of pressure.

Everything else I've done the comparison with has been within about 10% which is understandable so I was pretty surprised with the Hammer load.

I understand the difference in the AH vs the Hammer Hunter, Shock Hammer, etc. but I expected to see a higher chamber pressure not the difference in velocity.

Don't know if anyone else has run the numbers with any AH loads and found something similar.

 

[cohunt]

They hsve absolute hammer hunter bullets in quickload?

 

[LongWalker]

Yes. Most of the hammers are there. I'm sure some of the newer stuff is but the lion's share is.

 

[Mike D Texas]

Typically See higher actual velocities than calculated with the absolutes. It takes an update or two for them to get modeled correctly.

 

[adam32+P]

What is your weighting factor set to?

Quickload is actually quite complicated to get accurate numbers.

 

[LongWalker]

What is your weighting factor set to?

Quickload is actually quite complicated to get accurate numbers.

Factory setting I suppose as I didn't change it 0.55

 

[nksmfamjp]

What temps are you shooting at and have you put that into the powder settings?

@adam32+P Do you find the weighting factor to change your data much? I find it to be a less important factor.

 

[adam32+P]

What temps are you shooting at and have you put that into the powder settings?

@adam32+P Do you find the weighting factor to change your data much? I find it to be a less important factor.

Absolutely it will change the pressure data. As will Shot Start Pressure.

 

[Carey Farmer]

I wouldn't shoot any more of those loads. If your muzzle velocity is 200 fps over QL prediction with QL chamber pressure at max, you are WAY over max chamber pressure.

Hammer Bullets website suggests that "Muzzle velocity should not exceed max load velocity listed for similar weight bullets listed in loading manual. Muzzle velocity is an indication of pressure." 2963 fps is VV's published max N550 load velocity for 150 gr thin-jacketed cup-and-core bullets.

VV load data has max N550 load of 54.3 gr for Barnes TTSX 150 gr. Even the more generous max N550 load for 150gr Hornady SST (thin-jacketed cup-and-core bullets, which typically don't build as much chamber pressure as mono's) is only 55.2 gr.

I shoot 155 gr Absolute Hammers in a 28 Nosler. The rifle has about 300 rounds through it, so has plenty of heat checking at the lands and therefore elevated start pressures. I get a QL match on 155 Absolute Hammer muzzle velocity with QL starting pressure set to 10,000 psi. Don't see any ejector print on Nosler brand brass case heads until QL predicted chamber pressure (with 10,000 psi start pressure) is up to about 70,000 psi. That's consistent with what I see with other bullets in Nosler brass, with QL "tuned" to that bullet's start pressure. I haven't been brave enough to try to get ejector prints on Lapua, ADG or Peterson brass.

Anyway, you should try plugging 10,000 psi start pressure in QL and see what you get for predicted muzzle velocity. If still low compared to measured velocity, increase QL start pressure as high as 15000 psi (that's what I typically have to use to get a match for Barnes bullets). Once you get a match with muzzle velocity, take a look at the estimated chamber pressure.

 

[nksmfamjp]

Absolutely it will change the pressure data. As will Shot Start Pressure.

I agree it changes things, just less than SSP for example.

Anyway, you should try plugging 10,000 psi start pressure in QL and see what you get for predicted muzzle velocity. If still low compared to measured velocity, increase QL start pressure as high as 15000 psi (that's what I typically have to use to get a match for Barnes bullets). Once you get a match with muzzle velocity, take a look at the estimated chamber pressure.

@Carey Farmer 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.

 

[Zen Archery]

Weight Factor and starting PSI is not accurate in QL. I wouldn't use any data from QL for the Absolute Hammer Bullet line. Nothing I have done get it to line up accurately.

Just trust what your case is reading.

I typically pick a powder that is for a bullet weight 10-15 grains lighter. For example. If playing with 125gr Absolute Hammer bullet. I picked powders for 110gr Hammer Hunter Bullet powder choices. Again my method.

Like you when I put data in QL it's reading pressures 15-20k over with no case signs at all.

Trust your case not QL.

 

[Mike D Texas]

Weight Factor and starting PSI is not accurate in QL. I wouldn't use any data from QL for the Absolute Hammer Bullet line. Nothing I have done get it to line up accurately.

Just trust what your case is reading.

I typically pick a powder that is for a bullet weight 10-15 grains lighter. For example. If playing with 125gr Absolute Hammer bullet. I picked powders for 110gr Hammer Hunter Bullet powder choices. Again my method.

Like you when I put data in QL it's reading pressures 15-20k over with no case signs at all.

Trust your case not QL

Are you running the latest version of QL?

 

[Zen Archery]

Are you running the latest version of QL?

Yup.

 

[choprzrul]

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.