Lube Grooves - round or square?

[ryan richards]

Hi guys,

I have learned that lube grooves are to hold lube.

1) Do they serve another purpose?

2) Why are the grooves either round or square?

3) Is one better than the other?

[Ricochet]

One other purpose they serve is to provide a place for boolit metal displaced by the rifling lands to go. Otherwise the whole boolit gets squeezed and extruded as it goes into the rifling. They also can act as scrapers and pick up some debris from the bore.

[standles]

Round vs square = ease of machining.

Other than that I see no difference as long as they hold lube and (as the previous poster said) allow a place for squezzed metal to go.

Steven

[dakotashooter2]

Round vs square.

Round tend to drop from the mould a bit easier.

Square will hold just a bit more lube.

[NoDakJak]

All excellent answers! Neil

[TAWILDCATT]

sguare grooves are supposed to hold the lube in grooves better thats why Elmer Keith designed his with square grooves.

[felix]

More important is where the grooves are placed and their relative dimensions for boolits destined for long range shooting. Refer to thread: RPM Testing the 311291. ... felix

[Treeman]

Square bottomed grooves resist compression and bullet foreshortening better. Whether this is important is debatable but if you are pushing boolits hard, square is, at least theoretically, better.

[bohokii]

the grooves also reduce friction due to less bearing surface

[Southron Sanders]

Theoretically, grease grooves that are "square" will produce more "drag" on the bullet when it is flying downrange.

Whether or not this has a "real world" application, Idon't know. Anyone out there want to test this theory? Make up two identical bullet moulds except one have "square" grease grooves and the other have "angled" grease grooves and see how they shoot and how much velocity is retained downrange.