08-27-2018, 02:23 AM
Cajun,
Two more points...Unless your friend has drilled holes in his barrel it is physically impossible for your shorter 18" barrel to be faster than his 20", with the same ammo. At 18/20" we're talking about 50fps difference (roughly 25fps/inch). If your shorter gun is faster with the same ammo something is wrong with the measuring equipment or regime. You did say it's similar so it's not the same batch loaded by the same person. I am thinking for him to be slower than you his ammunition is milder and definitely not 'almost similar'. A grain or two makes a big difference when you are at the limit of the equipment. BTW, the loads I quoted above are not mild loads, they are on the edge of what I would call maximum.
Suppressors will never lower the velocity of your gun. Typically they add a few fps more due a phenomenon called 'freebore boost'. Suppressors are a containment vessel which allows expansion and cooling but still contains it. Even though the bullet is no longer sealed against the barrel walls there is still a bit more pressure behind the bullet as it passes through the suppressor than if it was the open air. This adds about 5fps more.
Two more points...Unless your friend has drilled holes in his barrel it is physically impossible for your shorter 18" barrel to be faster than his 20", with the same ammo. At 18/20" we're talking about 50fps difference (roughly 25fps/inch). If your shorter gun is faster with the same ammo something is wrong with the measuring equipment or regime. You did say it's similar so it's not the same batch loaded by the same person. I am thinking for him to be slower than you his ammunition is milder and definitely not 'almost similar'. A grain or two makes a big difference when you are at the limit of the equipment. BTW, the loads I quoted above are not mild loads, they are on the edge of what I would call maximum.
Suppressors will never lower the velocity of your gun. Typically they add a few fps more due a phenomenon called 'freebore boost'. Suppressors are a containment vessel which allows expansion and cooling but still contains it. Even though the bullet is no longer sealed against the barrel walls there is still a bit more pressure behind the bullet as it passes through the suppressor than if it was the open air. This adds about 5fps more.