Comparing Domed--Flat Ventliners
#1
Nontypical Buck
Thread Starter
Join Date: Aug 2008
Location: Rapid City, South Dakota
Posts: 3,732
Comparing Domed--Flat Ventliners
The past two days of shooting consisted of shooting the Omega Dream Season, 80g Blackhorn, 289g hard cast boolit, crush rib sabot, and W209 primer. The first shot each morning was made from a cold clean rifle, and breech plug. Two different vent liners were used; one each morning. Both vent liner have a flash hole 0.032" in diameter.
Yesterday the breech plug had the domed vent liner installed; a total of 10 shots were made.
Upon returning home the fouled breech plug, with the domed vent liner was weighed. The plug weighed 582.6 grain. Then the carbon in the flame channel was scraped/removed using a 5/32" drill. The plug then weighed 581.8 grain.
The flier on the target was not the first shot; it was the second shot.
It has warmed up here now, so a warming barrel was kind of an issue. The next two photo show the rifle being cooled this morning.
This morning the shooting was done with a flat vent liner in place. All things were the same as yesterday, except the vent liner was changed. As yesterday, ten shots were made, but the aim was changed from the middle to the bottom target.
At home the fouled breech plug with the flat vent liner was weighed. Weight was 572.1 grain. The Flame channel was cleaned with a 5/32" drill, and the breech plug weighed once again. Without the carbon/soot in the flame channel, the plug weighed 570.8 grain.
It appears the domed vent liner allowed 0.8 grain of soot/carbon into the flame channel, whereas the flat vent liner allowed 1.3 grain.
Yesterday the breech plug had the domed vent liner installed; a total of 10 shots were made.
Upon returning home the fouled breech plug, with the domed vent liner was weighed. The plug weighed 582.6 grain. Then the carbon in the flame channel was scraped/removed using a 5/32" drill. The plug then weighed 581.8 grain.
The flier on the target was not the first shot; it was the second shot.
It has warmed up here now, so a warming barrel was kind of an issue. The next two photo show the rifle being cooled this morning.
This morning the shooting was done with a flat vent liner in place. All things were the same as yesterday, except the vent liner was changed. As yesterday, ten shots were made, but the aim was changed from the middle to the bottom target.
At home the fouled breech plug with the flat vent liner was weighed. Weight was 572.1 grain. The Flame channel was cleaned with a 5/32" drill, and the breech plug weighed once again. Without the carbon/soot in the flame channel, the plug weighed 570.8 grain.
It appears the domed vent liner allowed 0.8 grain of soot/carbon into the flame channel, whereas the flat vent liner allowed 1.3 grain.
#4
Nontypical Buck
Thread Starter
Join Date: Aug 2008
Location: Rapid City, South Dakota
Posts: 3,732
#5
Nontypical Buck
Thread Starter
Join Date: Aug 2008
Location: Rapid City, South Dakota
Posts: 3,732
Repeat
This morning, and early afternoon, the shooting was repeated. The rifle was the same as before, as was the breech plug, the sabot, the primer, the distance, and the two different shaped vent liners. The target was the same except the holes from before were taped over. The scale was changed, a different scale was used to weigh the breech plug. The bullet was changed to a 250g XTP. The powder charge was changed to 100g Blackhorn. First up was the domed vent liner and 10 shots taken at the middle target beginning with a cold clean rifle, barrel, and breech plug. Then there was the trip home, the plug weighed, then reamed, then weighed again. The fouled breech plug with the dome liner in place weighed 586.5g. After the flame channel was reamed, the plug weighed 585.8g. The rifle and breech plug were cleaned, the flat liner installed in the plug, and the plug installed in the rifle. Back in the hills the flat vent liner was in place for 10 shots at the bottom target.
At home the breech plug was removed, and weighed. The flame channel was reamed, and the plug weighed again. The fouled plug weighed 575.5g; after reaming, the plug weighed 574.7g.
Today, the plug with the domed liner installed, had 0.7 g of soot in the channel, after 10 shots. When the flat liner was installed there was 0.8g of soot in the channel, after 10 shots.
At home the breech plug was removed, and weighed. The flame channel was reamed, and the plug weighed again. The fouled plug weighed 575.5g; after reaming, the plug weighed 574.7g.
Today, the plug with the domed liner installed, had 0.7 g of soot in the channel, after 10 shots. When the flat liner was installed there was 0.8g of soot in the channel, after 10 shots.
#6
HMMMMMM Hotter load= less soot. and MUCH less of a difference. But DAYUMN did that flat liner open up your groups! Damn near a shot gun pattern. But then again, you had groups within groups with the domed liner. Not a very good rest to shoot off of today maybe? Too much of the beerola last night? You usually shoot the squirrels nuts off with that Dream season.
#7
Nontypical Buck
Thread Starter
Join Date: Aug 2008
Location: Rapid City, South Dakota
Posts: 3,732
Had a nice solid rest. No toddy last night. Most all shots felt really good. Can shoot no better.
It was hot. It was windy. However, it didn't seem like the shots were wind blown much.
My excuse is the nodes and anti-nodes of the barrel were in the wrong place.
It was hot. It was windy. However, it didn't seem like the shots were wind blown much.
My excuse is the nodes and anti-nodes of the barrel were in the wrong place.
#8
And ya didn't hold yer mouth right either! Ya know that be THE most important thang!
#9
Nontypical Buck
Thread Starter
Join Date: Aug 2008
Location: Rapid City, South Dakota
Posts: 3,732
Final Comparison
This morning an exact repeat of the OP shooting, and loading was done.
For those interested, the tenth shot is the high hole; the first shot from a cold clean clean barrel is the next highest hole; the second shot is the hole just so barely inside the red 3/4" away from the first shot.
After the 10 shots, went to the house, removed the plug from the rifle, and the vent liner from the plug--then weighed the fouled plug @ 552.2 grain. Used a 5/32" drill to ream the carbon from the flame channel, and weighed the reamed plug @ 551.2 grain. In the OP, the vent liner wasn't removed for weighing.
Then headed out again with the clean rifle, but with the flat vent liner installed.
The second shot is the high hole of the five. Next, the tenth shot cozied right there in the group with the first shot, and shot nine cozied right next to shot two.
At home the fouled plug without the vent liner weighed 552.5 grain. The plug after reaming by the 5/32" drill weighed 551.3 grain.
In this final comparison, when using the domed vent liner there ended up being 1 grain of carbon coating the channel; whereas the flat vent liner allowed for 1.2 grain of carbon in the channel.
For those interested, the tenth shot is the high hole; the first shot from a cold clean clean barrel is the next highest hole; the second shot is the hole just so barely inside the red 3/4" away from the first shot.
After the 10 shots, went to the house, removed the plug from the rifle, and the vent liner from the plug--then weighed the fouled plug @ 552.2 grain. Used a 5/32" drill to ream the carbon from the flame channel, and weighed the reamed plug @ 551.2 grain. In the OP, the vent liner wasn't removed for weighing.
Then headed out again with the clean rifle, but with the flat vent liner installed.
The second shot is the high hole of the five. Next, the tenth shot cozied right there in the group with the first shot, and shot nine cozied right next to shot two.
At home the fouled plug without the vent liner weighed 552.5 grain. The plug after reaming by the 5/32" drill weighed 551.3 grain.
In this final comparison, when using the domed vent liner there ended up being 1 grain of carbon coating the channel; whereas the flat vent liner allowed for 1.2 grain of carbon in the channel.
#10
Boone & Crockett
Join Date: Apr 2007
Location: River Ridge, LA (Suburb of New Orleans)
Posts: 10,917
The test was interesting. Overall, with the mixed results of group size I could not conclude that one liner is better than the other. Though the flat liner groups do seem to be a bit more symmetrical/evenly spaced.