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Post by Richard on Apr 20, 2019 9:58:42 GMT -5
This is a post from a thread Herman put on concerning a brass HIS module that expanded while firing a charge of 68 gr. IMR-4227 and a 300 gr. bullet. There was a suggestion by Doug136 that the information provided by Educatedidiot be possibly kept as a "sticky?"---What say you Hank? So the reason I am reposting this is because the pertinent information would be buried in Herman's post and would be almost impossible to find, based on the title?
Richard
educatedidiot
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Lots of variables at work here but as a rule of thumb, the constants are:
Arrowhead standard modules begin expanding around 42kpsi
Arrowhead hard modules begin expanding around 52 to 55 kpsi
HIS standard modules begin expanding at around 48 to 52kpsi
HIS hard modules begin expanding at around 58 to 62kpsi. I've smoked one in a single shot at 65kpsi. So has Kyle
Please be mindful that flame channel volume plays a part in module failure because pressure builds faster in a smaller flame channel volume. Just like the old Savage plug. When we started into longer barrels and large doses of slower powder, we opened the flame channel inside diameter to avoid bulging 209 primers. This is why the Arrowhead modules fail at a lower pressure. They have a shorter, smaller inside diameter flame channel.
EI
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Post by Hank on Apr 20, 2019 19:20:28 GMT -5
So much for the shorter flame channel being a benefit, only cost you more money in the long run.
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Post by dunthat on Apr 20, 2019 19:44:43 GMT -5
Interesting...I've had experience with both systems...more so with the Arrowhead...My experience has been this...
Arrowhead standard modules...30+ shots per module @ 50+kpsi with no noticeable expansion
His standard modules...20+ shots per module @ 50k+psi with no noticeable expansion
Both of these were with 45 cal 73gn 4198 / 300gn bullets
Arrowhead hard modules 30+ shots per module @ 54kpsi...75gn H4350 / 300gn bullets ..with no noticeable expansion....375cal...standard modules showed expansion at this pressure in the .375
These pressure # 's were obtained using Quickloads...My real velocity numbers were very close to Quickloads estimated velocities making me think the PSI numbers are also close.
Not trying to be controversial...just stating my findings..I would be interested in seeing a more detailed conclusion to OPS numbers...
Think that both systems are great in their design.
Thanks Zen
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Post by doug136 on Apr 20, 2019 20:07:56 GMT -5
I just thought it was useful information. Gives a person some guidelines.
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Post by Richard on Apr 20, 2019 21:13:49 GMT -5
AS I know the source of the information, I can verify the numbers!
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Post by educatedidiot on Apr 20, 2019 22:34:01 GMT -5
As I stated, there are lots of variables at play. This is not intended to be a one system is better than the other deal. Both standard modules are machined from similar brass stock which have similar pressure limits. The hard modules are machined from 630 bronze (Aluminum Nickel Bronze) which has a higher pressure limit. The difference being the flame channel volume. As with most things in life, it is a give and take relationship when materials stay the same but the forces they are subjected to change. By designing a smaller/shorter flame path, pressures on the module are increased and with longer barrels it is maintained for a longer duration. In the end, it is hard to beat DI. Thanks Phil. 1) Pressure vs time. When the initial charge spikes, pressure is applied to the bushing which meters the flow via it's orifice of .030, .035, .040" into the flame channel. Obviously, the larger bushing orifice allows pressure to enter the flame channel at a faster rate. At this point, the time the projectile is in the barrel (barrel time) is a huge factor. For a given chamber pressure, the flame channel is filled at a given rate. The longer pressure is applied (barrel time) the more pressure that builds inside the flame channel, which is directly exposed to the module. This pressure also must escape thru the bushing after the bullet exits the barrel. This is why Luke sold 25" barrels for so long, because as they get longer the 209 primers began bulging. 2) Quick Load can be manipulated in so many ways that each one of us could come up with different calculated pressures, velocities, etc. For those that do not trace, the next best thing is manipulating the load in QL to match measured velocities. In our application, using this method, the calculated pressure is rarely close because of the inherently low bullet to bore friction. I can pretty accurately predict chamber pressure and barrel time using a method I've proven out, but the calculated velocity will not be correct. Barrel time gets me on the node in very few shots and my calculated pressures are real close to actual strain gauge measured pressures. This way I can save a lot of components by being on the node quick and I shouldn't have any high pressure surprises. The fellow I buy my tracing supplies from at RSI always gets a quick laugh in when I mention QL. He says it is a joke because we can manipulate it to give what ever we want. For my use, it has served me well and kept me safe since we are regularly shooting 40 cal loads around 60kpsi with modules and even beyond with DI. QL is a handy tool that must be respected AND backchecked by any and all means.
EI
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Post by hammer on Apr 21, 2019 1:00:20 GMT -5
As I stated, there are lots of variables at play. This is not intended to be a one system is better than the other deal. Both standard modules are machined from similar brass stock which have similar pressure limits. The hard modules are machined from 630 bronze (Aluminum Nickel Bronze) which has a higher pressure limit. The difference being the flame channel volume. As with most things in life, it is a give and take relationship when materials stay the same but the forces they are subjected to change. By designing a smaller/shorter flame path, pressures on the module are increased and with longer barrels it is maintained for a longer duration. In the end, it is hard to beat DI. Thanks Phil. 1) Pressure vs time. When the initial charge spikes, pressure is applied to the bushing which meters the flow via it's orifice of .030, .035, .040" into the flame channel. Obviously, the larger bushing orifice allows pressure to enter the flame channel at a faster rate. At this point, the time the projectile is in the barrel (barrel time) is a huge factor. For a given chamber pressure, the flame channel is filled at a given rate. The longer pressure is applied (barrel time) the more pressure that builds inside the flame channel, which is directly exposed to the module. This pressure also must escape thru the bushing after the bullet exits the barrel. This is why Luke sold 25" barrels for so long, because as they get longer the 209 primers began bulging. 2) Quick Load can be manipulated in so many ways that each one of us could come up with different calculated pressures, velocities, etc. For those that do not trace, the next best thing is manipulating the load in QL to match measured velocities. In our application, using this method, the calculated pressure is rarely close because of the inherently low bullet to bore friction. I can pretty accurately predict chamber pressure and barrel time using a method I've proven out, but the calculated velocity will not be correct. Barrel time gets me on the node in very few shots and my calculated pressures are real close to actual strain gauge measured pressures. This way I can save a lot of components by being on the node quick and I shouldn't have any high pressure surprises. The fellow I buy my tracing supplies from at RSI always gets a quick laugh in when I mention QL. He says it is a joke because we can manipulate it to give what ever we want. For my use, it has served me well and kept me safe since we are regularly shooting 40 cal loads around 60kpsi with modules and even beyond with DI. QL is a handy tool that must be respected AND backchecked by any and all means.
EI
This is the best explination I have ever seen about how variations of bushing size, flame channel volume and barrel time effect the stress on the ignition module being used. |
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Post by hillbill on Apr 21, 2019 7:51:54 GMT -5
Educated? Yes! Idiot? Don't think so!
Yes that's a good explanation, it has proven out over time and I can tell you his calculation for hitting a node is spot on.
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Post by doug136 on Apr 21, 2019 8:26:32 GMT -5
This is why Luke sold 25" barrels for so long, because as they get longer the 209 primers began bulging.
[di
That sentence makes sense and explains some things.
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Post by doug136 on Apr 21, 2019 8:29:26 GMT -5
I am sooo glad educatedidiot is back ! I mean here . 🥴
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Post by Richard on Apr 21, 2019 8:56:16 GMT -5
The reason for this post is also to illustrate why we should not deviate from the topic in an original post? If you have a new idea, start a new thread!
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Post by jimbob on Apr 21, 2019 11:52:58 GMT -5
Very informative thanks EI
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Post by olebud on Jun 6, 2019 12:14:05 GMT -5
Thanks EI.... very good intel
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hueff
New Member
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Post by hueff on May 6, 2021 10:28:11 GMT -5
Is similar information available for Jeff Hankins' DI (Direct Ignition) system?
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Post by hillbill on May 7, 2021 4:54:01 GMT -5
DI which was conceived by Phil Juslus, (forgive me if I got the name wrong Phil) will have no pressure indicator until it smokes a primer or even the module itself, I have seen it happen. It uses a grade 9 aircraft 12 point bolt that is very hard, Jeff machines them to accept a primer after drilling a hole thru them. DI is a hotter ignition source due to the fact it has no bushing and a large flame path to the powder, some of us are using it in bolt guns but most DI use is in break action guns, it's easier to manipulate in the break action and I like it because I can eliminate the extractor and take the plug out at will. DI makes about 3K PSI (estimate) more pressure than modules with the same load so you must use accordingly. Direct can be beneficial if you are trying to swell a bullet quicker or in mine and others case using a combo that is hard to obturate such as a long Aeromax 350 in the .40 cal with very slow powder.
DI has it's down sides: having to load with a module in place which is no big deal especially in a bolt gun because the bolt is removed from the gun, in a break action for ultimate safety you can load with the action broken down. In my Apex I carry a dummy module that I place in the gun at the end of the day so it is legal upon leaving the field DI requires a magnet being glued into the socket to remove and replace modules, easy to do. It's definitely slower than modules and requires the use of a tool.
Is DI for everyone? NO, it has it's place though. Many have found lower extreme spreads with DI and some like me like it overall better in a break action but each to his own.
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Post by mantaray96 on Jan 17, 2022 22:21:43 GMT -5
My experience with the DIS module. I drilled out the CVA breech plug and tapped it for the DIS module. Also removed approximately .130 for correct head space. Leaves about .100 of hex for socket to grip. No modification to bolt face. Using 105 grains by weight of BH 209 with a 300 grain bullet, (swaged to .4532). With this combination I had two primers blowout. I removed the breech plug and noticed the thin ring section at the end was bulged out. Opps! a sign of over pressure. I was surprised in consideration to BH 209 causing over pressure. You would think it is safe and 105 is a normal charge. It was a mystery until I read about the extra pressure that the DIS module can create. However this can be a good thing as in using less BH 209 to produce the same pressure. I reduced to 91 grains by weight with good accuracy. Do not know velocity readings and shooting 100 yards
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