Direct Ignition
04-11-2017, 11:34 AM
#1
Nontypical Buck
Thread Starter
Join Date: Aug 2008
Location: Rapid City, South Dakota
Posts: 3,732
Direct Ignition
Scott is/was quite interested in seeing how Blackhorn works with direct ignition. Achieving direct ignition is trivially easy to do if one has a breech plug with a vent liner; alls one need do is remove the vent liner, and use the plug without. The first time i tried this was in 2012. Back then i used a shotgun primer, and it didn't work so good. The primer leaked soot between the anvil, and cup; the primer required a leatherman tool to remove it from the breech plug. This morning a Fedral 215 primer was used.
This morning a pr adapter was used in a modified QRBP. The adapter allowed the Federal 215 magnum rifle primers to be used.
An o-ring was was used in the primer socket to stop blow by around the nose of the adapter. The first three shots beginning with a clean cold barrel were made with the vent liner in place.
Then the vent liner was removed.
Without the vent liner in place the powder nestles right up tight to the primer adapter, and it is as though one is using a cartridge filled with powder. Three shots were made on the target using 'direct ignition'. The adapters came right out of the breech plug using fingers.
Then a chronograph was set up in shade, and bullet speed was measured about 15' from the rifle. The load was 65 (weighed) grain Blackhorn, 265g 44 caliber FP interlock, smooth green Harvester sabot, Federal 215 primer. Rifle was an Optima with a 4X scope mounted.
First shots clocked were with the vent liner reinstalled in the breech plug.
1736 fps
1724
1736
1732 fps = average with vent liner
Next five shots made without a vent liner; powder right up tight to the primer.
1823 fps
1782
1836
1801
1841
1816 fps = average
The last photo shows the primers/adapters after. The primers to the right of the vent liner, fired with the vent liner in place.
__________________________
This morning a pr adapter was used in a modified QRBP. The adapter allowed the Federal 215 magnum rifle primers to be used.
An o-ring was was used in the primer socket to stop blow by around the nose of the adapter. The first three shots beginning with a clean cold barrel were made with the vent liner in place.
Then the vent liner was removed.
Without the vent liner in place the powder nestles right up tight to the primer adapter, and it is as though one is using a cartridge filled with powder. Three shots were made on the target using 'direct ignition'. The adapters came right out of the breech plug using fingers.
Then a chronograph was set up in shade, and bullet speed was measured about 15' from the rifle. The load was 65 (weighed) grain Blackhorn, 265g 44 caliber FP interlock, smooth green Harvester sabot, Federal 215 primer. Rifle was an Optima with a 4X scope mounted.
First shots clocked were with the vent liner reinstalled in the breech plug.
1736 fps
1724
1736
1732 fps = average with vent liner
Next five shots made without a vent liner; powder right up tight to the primer.
1823 fps
1782
1836
1801
1841
1816 fps = average
The last photo shows the primers/adapters after. The primers to the right of the vent liner, fired with the vent liner in place.
__________________________
04-11-2017, 12:14 PM
#3
Nontypical Buck
Join Date: Mar 2009
Location: Saxonburg Pa
Posts: 3,925
Ron,
Im stating this thinking your using a factory CVA plug you modified?? I would be very careful doing what your doing with that plug. Its obviously very weak material and its not designed to take all that pressure that your putting on it. That 5/32 flame channel or even 1/8 will hold powder in it. The reason your seeing higher velocity is because of more pressure building in the flame channel aside from the barrel. I honestly wouldnt do this with a Lehigh 17/4 plug with ventliner removed. Very dangerous!!!
Im stating this thinking your using a factory CVA plug you modified?? I would be very careful doing what your doing with that plug. Its obviously very weak material and its not designed to take all that pressure that your putting on it. That 5/32 flame channel or even 1/8 will hold powder in it. The reason your seeing higher velocity is because of more pressure building in the flame channel aside from the barrel. I honestly wouldnt do this with a Lehigh 17/4 plug with ventliner removed. Very dangerous!!!
04-12-2017, 07:10 AM
#5
Giant Nontypical
Join Date: Mar 2010
Posts: 5,605
The screw in modules i showed you take the "back thrust" of ignition. Using the PR modules the action takes that thrust in a relatively small area. I would not be concerned about the plug holding up. I would be concerned about a SS module beating on the steel firing pin bushing which is in a alloy frame.
The screw in modules are Grade 9 and so far are working well in steel frame break actions and true bolt actions. IMO they should be safe if using BH209 in almost any action. Unfortunately the vendor wont sell just the screw in LRMP modules. They are around $125 for 10 with a breach plug.
Thank you though Ron. It turned out as i suspected. There was a very noticeable fps gain with direct ignition and BH209.
The screw in modules are Grade 9 and so far are working well in steel frame break actions and true bolt actions. IMO they should be safe if using BH209 in almost any action. Unfortunately the vendor wont sell just the screw in LRMP modules. They are around $125 for 10 with a breach plug.
Thank you though Ron. It turned out as i suspected. There was a very noticeable fps gain with direct ignition and BH209.
04-12-2017, 09:57 AM
#7
Nontypical Buck
Thread Starter
Join Date: Aug 2008
Location: Rapid City, South Dakota
Posts: 3,732
Made it out again this morning, and did some more shooting. The load was 70 (weighed) grain Blackhorn, 275g BE, short black Harvester sabot, Federal 215 primer.
Earlier this week i had modified an Omega breech plug to use the pr adapters This Omega breech plug does not use a vent liner; it has the flame channel, and flash hole in place; not direct ignition. The Omega rifle came with, so he was given a chance to shoot the target using rifle primers. Load was 60 (weighed) grain Blackhorn, 265g 44 caliber FP interlock, green crush rib sabot, Federal 215 primer. Range was 100 yard.
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Earlier this week i had modified an Omega breech plug to use the pr adapters This Omega breech plug does not use a vent liner; it has the flame channel, and flash hole in place; not direct ignition. The Omega rifle came with, so he was given a chance to shoot the target using rifle primers. Load was 60 (weighed) grain Blackhorn, 265g 44 caliber FP interlock, green crush rib sabot, Federal 215 primer. Range was 100 yard.
Originally Posted by bestill
....Use caution with direct ignition
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04-12-2017, 06:20 PM
#9
Nontypical Buck
Thread Starter
Join Date: Aug 2008
Location: Rapid City, South Dakota
Posts: 3,732
That is exactly what the Blackhorn QRBP is. It has a short flame channel compared to the QRBP that comes with the rifle, and it doesn't require an adapter. Also, because it has a flash hole, and a flame channel which absorb pressure, it is much much safer than direct ignition.
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Originally Posted by bestill
.......Use caution with direct ignition
_________________________
07-14-2017, 11:07 AM
#10
Giant Nontypical
Join Date: Mar 2010
Posts: 5,605
A 45cal sabotless pressure trace was run recently using direct ignition, 300gr BE and 120grV of BH209. The pressure was 28.7kpsi and about 2230fps. As a comparison a similar trace was run a while back using a 300gr Rem and a 209 Savage plug. Swinglock also did a trace using his 209 system with 120grV and a FULL FORMED 350gr.
Peak pressure for the Savage 209 plug was only around 26kpsi and fps was close to 2100fps. The Swinglock 350gr trace had about the same peak (26kpsi) and gave about 2000fps.
Peak pressure for the Savage 209 plug was only around 26kpsi and fps was close to 2100fps. The Swinglock 350gr trace had about the same peak (26kpsi) and gave about 2000fps.
Last edited by Gm54-120; 07-14-2017 at 11:11 AM.