Hidden Pressure Reading: A Method

[MagnumManiac]

Tony, do you by any chance have a list of which ADI powders have exact equivalent in Hodgdon, IMR or other? I see table on the ADI webdsite, but not sure which ADI are sold by another "name"

What the ADI/Thales website say is accurate.
For example.
Extreme line:
Trail Boss/Trail Boss
AR2205/H4227
AR2207/H4198
Bencmark 1/not distributed
AR2219/H322
Benchmark 2/Benchmark
AR2206/BLC(2) discontinued
AR2206H/H4895
AR2209/H4350
AR2213sc/H4831sc
AR2217/H1000
AR2225/Retumbo
AR2218/H50BMG
I have not included Bench Mark 8208, unsure of Hodgdon designation.
Also haven't included pistol/shotgun powder, an example is AP/S 30N/Clays. It appears they have dropped several pistol powders since I worked there, but AP/AS50N is still made and is HP-38 for pistol and International for shotgun, both having different coloured dots in the powder, like the yellow discs in Clays.

Cheers.

 

[MagnumManiac]

Guys, is it possible to have occasional stick bolt lift and not have high pressure.

Yes, cratered primers, caused by a gun issue, can cause sticky rotation of the bolt. Cases not sized enough can cause it and even a foreign substance, like dust, can cause it. A dirty bolt etc.

Cheers.

 

[asd9055]

What the ADI/Thales website say is accurate.
For example.
Extreme line:
Trail Boss/Trail Boss
AR2205/H4227
AR2207/H4198
Bencmark 1/not distributed
AR2219/H322
Benchmark 2/Benchmark
AR2206/BLC(2) discontinued
AR2206H/H4895
AR2209/H4350
AR2213sc/H4831sc
AR2217/H1000
AR2225/Retumbo
AR2218/H50BMG
I have not included Bench Mark 8208, unsure of Hodgdon designation.
Also haven't included pistol/shotgun powder, an example is AP/S 30N/Clays. It appears they have dropped several pistol powders since I worked there, but AP/AS50N is still made and is HP-38 for pistol and International for shotgun, both having different coloured dots in the powder, like the yellow discs in Clays.

Cheers.

Thank you Sir. I Have their website. I never searched for it till the lates exchange on this thread. Very informative. I appreciate it.

 

[Mike Matteson]

I think if you get to bolt lift stiffness you're beyond primer pocket longevity. Having a sacrificial case to "load to pressure" is what I've done. Then back off a grain, then reduced .3gr till I found accuracy.

I think if I monitor my Lapua brass from the start and keep the primer pockets to no growth to under .210 I won't need to hit the bolt lift sign.

I hadn't look at it that way, but it seem reasonable. I'll have to start looking at that way. Me I have read my primers most of my life. I feel I am petty good at that. As I am developing a load for my rifle I watch that. Watch my primers for signeds. If I get a creatored primer, but I generally stop before getting there. I stop there and back off some. I generally do a run up on powder loads, depending on just how much the case will hold. Start off at low manual load and increase by either .25grs to .5grs of powder increase by case volume. At the same time chronographs watching the velocities. Doing a ladder test of type. I haven't worked on bullet setback at this time. It's my understanding it can be done. If increasing your powder loads by 1/2"gr I feel it kind of hard to see how grouping is going to work with changing the distance from the lands at the same time. To me to many IF's. Also getting into possible change in chanber pressures.
I do see the value in distance from ogive to lands for grouping, but at the same time it changing your chamber pressure.
I know that some people use cooler to kept there ammo in or in a pocket to keep them warm. depending on weather.
I work on cold bore shots no matter what the weather is. If it doesn't put it on the money I won't use it.

 

[Muddyboots]

Reading pressure? Published bullet or powder load data with stated max loads at SAAMI specs have provided good lines in the sand for me recognizing the load data is based on their barrel, their brass, their primer lot number and their powder lot number. We tend to overlook basic understanding their firearm is different, creates pressure differently, different bullet seating depths, and we use identical components of different lot numbers that may result in different pressures. Heck, sometimes similar components but not identical. The "quest" to exceed this published data is not worth the ROI IMO. Extra 50fps is meaningless to me. Loading is still physical science, exceed firearm parameters and SHTF. When a load is on the cusp, any minuscule change; in loading, ambient temperature, environmental conditions, rough handling of ammo, rifle changes, fouling of bore by outside forces etc can change from on the cusp to SHTF. STORAGE can take a load on the cusp to over the edge due to cold weld or other storage factors.

The need to read pressure for custom bullets whether cup and core or mono's that does not have published data is where the rubber meets the road. The discussion on primer observations, brass case head observations, brass web measurements, chronograph readings and bolt lift are all potential indicators to stop. Be aware of chronograph readings and velocity flattening plateaus. Every case must be inspected for primer observations, brass observations and brass measurements. The process of seating primers is one of the most telling factors just by feeling the amount of force to seat a new primer. Heads up, a PSA: if you can seat primer with your thumb, you may want to back down loads. This force to seat primers over time is a feeling that you just KNOW when it is still good to go.

I just listened to a Hornady podcast on their load data by one of their ballistic guys and was surprised a bit. Their loads are ALL developed in a pressure barrel contrary to a lot of opinions I have read on their data. They discussed the opinion the load data is generated by lawyers. Emphatically stated the load data is generated by pressure barrels to SAAMI maximum pressure for each cartridge. The load data is based upon pressure measurements. The published data will show a rifle which is used to VERIFY the loads. They mentioned Hodgdon data is also generated in similar pressure barrels but just like component differences, results can be different. They stated it and the truth is somewhere. The podcast is #82 Load Data if interested.

So who or what do you believe? Me? I trust what I can verify for myself. Otherwise simply known as: trust but verify.

The one statement that is so freaking ABSURD: "My rifle can take it....until it doesn't."

 

[nksmfamjp]

Of all the metrics available to the layman loader, case head and web expansion are the most accurate.

Probably, but I would need a blade micrometer and a jig to get any meaningful data!

Guys, is it possible to have occasional stick bolt lift and not have high pressure.

Depends on what cases it. If cases start super tight, they will end super tight. ..even with light pressure.

I just listened to a Hornady podcast on their load data by one of their ballistic guys and was surprised a bit. Their loads are ALL developed in a pressure barrel contrary to a lot of opinions I have read on their data. They discussed the opinion the load data is generated by lawyers. Emphatically stated the load data is generated by pressure barrels to SAAMI maximum pressure for each cartridge. The load data is based upon pressure measurements. The published data will show a rifle which is used to VERIFY the loads. They mentioned Hodgdon data is also generated in similar pressure barrels but just like component differences, results can be different. They stated it and the truth is somewhere. The podcast is #82 Load Data if interested.

If you listen close to their words and actions from an engineering perspective, I hear them use tight barrels, tight chambers and that all produces max pressure and not necessarily max velocity. So their data is on the conservative side. Additionally they don't show you their pressure measure numbers….everybody draws a line somewhere in the safe zone.

 

[Muddyboots]

If you listen close to their words and actions from an engineering perspective, I hear them use tight barrels, tight chambers and that all produces max pressure and not necessarily max velocity. So their data is on the conservative side. Additionally they don't show you their pressure measure numbers….everybody draws a line somewhere in the safe zone.

100%. All pressure test barrels are at tightest of specs which will hit SAAMI pressure at SAAMI measurements prob faster established for cartridge. When we seat bullet out closer to leade, pressure curves associated with SAAMI do not line up. There are a lot of variables between published data and what a lot of us do.

It was interesting they even mentioned they don't show pressure.

 

[Rich Coyle]

Most experienced loaders have a go/ no go guage , to check the pocket for excessive enlargement. If the no go end fits throw the case away. If your finding that after a few loadings your loads are toooo much pressure! Back off your asking toooo much from your firearm.

I guess I must not be in the majority. I've been loading for more than 40 years and never heard of a go/no go gauge for primer pockets.

 

[Rich Coyle]

You guys are free to do whatever you want, but I really can't believe how many times this has to be repeated. If you are getting hard bolt lift you are WAY WAY past pressure limits. You are north of 90,000 PSI and past even proof test loads. If you are losing primer pockets after 1 or 2 firings, even on soft bras, you are Way past pressure limits. All of the traditional pressure signs, flat primers, ejector marks etc are well over the proper pressure.

Hodgdon publishes the pressure for all their loads, and these are all 100% tested. Different guns, powder, brass will give slightly different results but if you think you can significantly exceed their velocity or loads you are just fooling yourself. If you think loads have been lawyered, call Hodgdon. They will confirm that better testing equipment and current powder profiles is what has lead to current loads.

Like I said at the start, guys are going to do whatever they want, but I am glad I don't have to share a range with guys shooting 100,000 PSI loads.

How many guns have you heard of being damaged or destroyed by using bolt lift resistance for testing for pressure?

 

[VinceMule]

Rich, I think that the problem that everyone worries about is metal fatigue.

 

[DoneNOut]

I guess I must not be in the majority. I've been loading for more than 40 years and never heard of a go/no go gauge for primer pockets.

I'm just a nobody, but I figured to use a #4 drill bit smooth end that measures .211 as a go/no-go. Or just set aside the ones that primed without positive resistance, punch the primers and then shrink the primer pocket with a ball bearing and hardened bolt.

 

[VinceMule]

+1

I de-prime with a hand primer, this is a GREAT indicator of a loose primer pocket. That #4 drill is one heck of an idea!

 

[nksmfamjp]

I guess I must not be in the majority. I've been loading for more than 40 years and never heard of a go/no go gauge for primer pockets.

Small and Large Primer Pocket Swage Gage ® Set

Swage Gage Small Primer Pocket Gauge

ballistictools.com

How many guns have you heard of being damaged or destroyed by using bolt lift resistance for testing for pressure?

none.

Rich, I think that the problem that everyone worries about is metal fatigue.

Fatigue is all about cycles typically they are focused on life out to 1 million cycles. Somehow I'm hoping I never reach 1 million rounds at max pressure.

 

[Mike Matteson]

Reading pressure? Published bullet or powder load data with stated max loads at SAAMI specs have provided good lines in the sand for me recognizing the load data is based on their barrel, their brass, their primer lot number and their powder lot number. We tend to overlook basic understanding their firearm is different, creates pressure differently, different bullet seating depths, and we use identical components of different lot numbers that may result in different pressures. Heck, sometimes similar components but not identical. The "quest" to exceed this published data is not worth the ROI IMO. Extra 50fps is meaningless to me. Loading is still physical science, exceed firearm parameters and SHTF. When a load is on the cusp, any minuscule change; in loading, ambient temperature, environmental conditions, rough handling of ammo, rifle changes, fouling of bore by outside forces etc can change from on the cusp to SHTF. STORAGE can take a load on the cusp to over the edge due to cold weld or other storage factors.

The need to read pressure for custom bullets whether cup and core or mono's that does not have published data is where the rubber meets the road. The discussion on primer observations, brass case head observations, brass web measurements, chronograph readings and bolt lift are all potential indicators to stop. Be aware of chronograph readings and velocity flattening plateaus. Every case must be inspected for primer observations, brass observations and brass measurements. The process of seating primers is one of the most telling factors just by feeling the amount of force to seat a new primer. Heads up, a PSA: if you can seat primer with your thumb, you may want to back down loads. This force to seat primers over time is a feeling that you just KNOW when it is still good to go.

I just listened to a Hornady podcast on their load data by one of their ballistic guys and was surprised a bit. Their loads are ALL developed in a pressure barrel contrary to a lot of opinions I have read on their data. They discussed the opinion the load data is generated by lawyers. Emphatically stated the load data is generated by pressure barrels to SAAMI maximum pressure for each cartridge. The load data is based upon pressure measurements. The published data will show a rifle which is used to VERIFY the loads. They mentioned Hodgdon data is also generated in similar pressure barrels but just like component differences, results can be different. They stated it and the truth is somewhere. The podcast is #82 Load Data if interested.

So who or what do you believe? Me? I trust what I can verify for myself. Otherwise simply known as: trust but verify.

The one statement that is so freaking ABSURD: "My rifle can take it....until it doesn't."

Got that right on seating primers. I do work on velocity, but it has to be accurate at the same time. Otherwise it's no good for me. Got to know how you load is going down range. That all there is to it. No heavy bolt lift right off the top. I read about people saying that there is ejector marks, but not big deal. That away beyond my loads. I get pi**ed off at myself if I get to where there starting to show ejector marks.
To me if I am changing powder amounts and primers, or seating depth. I'll back off and work on all at the same time. That being amount of powder, and if I am changing primers in seating depth. I look at the closer I get my bullet to the lands, the more chamber pressure there is. I do work on seating depth or distances from the lands. That generally a reduced load to start with, then increase the powder and velocity after finding what seating depth I going to use. Still watching and inspecting all the time. That one of the reasons I scale all my powder loads. i use to weight my brass, now I volume weight my brass. I'll go the extra mile to get it done correctly, and study the load I have come up with in all types of weather. That way if I miss, it's my fault not the rifle or weather. if you can't put the faith in your rifle, you are doing something wrong, or the rifle has a problem.
I also realize that judging by how your primer looks isn't the best way, but I use it. In my belted mag's I am generally over the manual by several grains of powder anyway, so I know, I have a hot load to start with. No ejector marks or creator primer either.