G5 summary narrative
Jun 11, 2010 9:41:24 GMT -5
Post by Harley on Jun 11, 2010 9:41:24 GMT -5
I've finally finished all my observations and tests on the G5 Montec CS. I'm pulling together in this new thread bits and pieces from two or three other threads that have hit on aspects of the G5, arrow selection and tuning. My intent is to present a narrative of testing that will aid a first time viewer in understanding some of the variables that go into setting up a good hunting outfit.
--------------------------
I've discovered that, when building an arrow, there are different ways to compute Front of Center (FOC) and different measurements to be used in those computations, none of them better than any other if you regard them as measures of relative performance among components. One of those I used showed no difference in FOC between combo field points and the fixed blade Montec CS, with an FOC of 14.3%. The main measurement influencing that result was assuming the total arrow length to be from the nock pocket to the end of the shaft behind the insert.
I've also computed a different formula which utilizes a total arrow length from the nock pocket to the actual tip of the point. With the Montec CS the resulting FOC was 10.9%; with the field tip the FOC was 12.4%. I think the reason the field tip has a higher FOC is because it has more weight concentrated in the very end of the tip than the raked back broad head.
Since Easton regards 7-15% FOC as acceptable I'm satisfied that I'm in the ballpark.
I doubt that the 1.4% difference in FOC between my broad head and field point will result in any significantly measureable difference on target AT ANY RANGE. You are not changing weight distribution around the longitudinal axis of the shaft by switching from a field point to a broad head IF (big IF) the broad head is both symmetrical with regard to its blades and centered with regard to the shaft. For instance, 100 grains is 100 grains, whether it's field point or broad head, and the FOC is not changed significantly when you replace the field point with the same weight broad head.
I recently read, and tend to believe, that there should be no need to "tune" broad heads; that they require no more than being absolutely aligned and symmetrical. Given that, they should hit POI where the field points hit. Anyway, I can't tune my broad heads because I've epoxied the inserts into my shafts.
I would add two observations, though:
1. Probably very few broadheads are that well centered.
2. There's always the chance that your broad head may require more steering than your present fletching provides.
I'm not arguing that most people won't have to tune their broad heads, but it's because their broad heads don't meet the specifications I've set up.
Of much more concern to me is whether or not the relatively small, slightly offset 2" Blazers will be able to steer the broad head at longer ranges to the target. I'm thinking that "tuning"; i.e., aligning the blades with the vanes is not the answer, although it can't hurt. If the Blazers won't steer the broad head, maybe I should try either longer and/or taller vanes and/or more helical. I don't want to do anything, of course, both because of the effort involved and the fact that any of the above modifications would slow the arrow.
I've always tuned my setup without a quiver and always remove the quiver once I'm in my stand.
It's not important to me that the fixed blades hit the same POI as my field points; worst case scenario is to tune the bow for them before hunting season.
For testing, I bought two 3-packs of 100gn G5 CS, one 3-pack of pre-season practice heads and the sharpening stone.
First, I tested sharpness against hair on my arm; they cut as well as any I've ever tried, what someone called "scary sharp"; so, I'm no longer worried about that. I've never tried the regular G5's, so don't know if they are as sharp as the CS, but I suspect they aren't.
The sharpening stone looks great, and the cordura case is perfect for it.
The pre-season practice blades are colored black and coated with a slippery substance for easier target removal. Look good.
Next, I weighed all the blades on my RCBS Chargemaster 1500 digital scale (claimed reliability + or - .1 gn). Each blade was weighed twice and I kept the different packs apart in order to test variances among "lots".
Pre-season blades:
102.4
102.8
102.8
The average was 102.7 gns. The spread among them was .4 gns.
Lot 1 100 gn G5 CS:
98.5
98.9
98.2
The average was 98.5 gns. The spread among them was .7 gns.
Lot 2:
98.9
97.9
98.5
The average among them was 98.4 gns. The spread was 1.0 gn.
In the real world, the overall extreme spread of 1 gn among the six points means nothing, but the lightest of them is 2.1 gns lighter than advertised; and the average weight is ~ 1.5 gns light.
The practice points are within .4 gns of each other, but still average 2.7 gns heavier than they should be.
Conclusion:
I expect the practice points to group together, but I'll still have to shoot the "real" points to confirm zero-in for hunting season.A grain and a half lighter hunting tip will move the F.O.C. back a bit, but not significantly.
The dull practice G5's penetrate the target 4-6 inches deeper than the field points of the same weight.
The field points and the practice G5's have the same point of impact.
Because my inserts are epoxied, I couldn't rotate them to "tune" the broadhead with the Blazer vanes. Although the blades ended up in various degrees relative to the vanes, I didn't see any effect at all.
The practice blades would quickly destroy either a target or my Glendale buck; they are too dull to cut as you pull them back out, so they would be either trapped or pull the stuffing out of the target. I've decided to retire them, and shoot the actual broad head at targets, then re-sharpen them.
I missed the entire target with one shot and the G5 broad head buried about half its length in a Sweet Gum tree. I had to use a hammer and chisel to retrieve it. The good news is it wasn't damaged, and would STILL shave hair on my arm. If I can ever dull them, I'll try the new sharpener. They are still sharp after maybe 15 shots each.
I shot until failing light at 20 yards with the hunting G5's; when I could call my shots; i.e., know that I did everything correctly, I got ~ 1" groups.
I'm shooting the 60# pound bow set at 50# because it pains me less; if anything, this reduced draw weight should result in a sloppier performance from the bow, but it doesn't seem so.
I'm in the middle of a learning curve with the G5 sharpening stone; spent some time sharpening my G5 broadheads. It's no trick to get them to the point of cleanly cutting paper, but I'm having trouble making them hair-shaving sharp. I think I just need to practice.
I've now scraped so much hair from my arm with the G5 broadheads that it looks as if it's been licked by a tiger. I'm finally more or less satisfied; what sharpening boils down to is an "art", not a "science". The directions use words like "moderate pressure" and "light pressure" and "3-12 repetitions". What's "light" mean, or "moderate"? I just had to keep on working at it until I got it. I think I can get the points sharper over time, but have every confidence they are sharp enough, right now.
All I have left to do before completely endorsing the G5 is to shoot it at extended ranges as a check on "steering".
Final testing:
At daybreak this morning the wind was calm and the forecast was rain later in the afternoon, so I loaded up and went to a nearby church parking lot to shoot. There is a berm there that fronts the volleyball court and makes a fairly good but sloping away backstop. Nobody was around so I decided I didn't need a permit
I set my 2x2 target so that I was facing south, but as luck would have it, being left handed, I was staring to the east at the rising sun. That was not only uncomfortable, but the resulting squint cost me some sharpness looking at the target at the longer ranges I eventually shot.
Setup:
Bow: Mathews Z7, 60# design weight, set at 50#. Q.A.D. drop-away rest. Anchor Sight (peep substitute). Vital Gear Star Pro slider bow sight. Single caliper release. D-loop.
Arrows: Redhead (BassPro) Carbon Maxx 2000, 7.3 gpi, 26 5/8ยจ length from bottom of nock pocket to behind insert. Q.A.D. nock. 100 gn point, either combo field tip or G5 Montec CS. Front of center (FOC) variously calculated between 10.9% and 14.3%.
Muzzle velocity: 273 fps at 50# draw weight; measured three feet in front of chrony
Methodology: Beginning at 20 yards, zeroed the target with field points, then shot broadheads into the resulting group without first removing the field tip arrows. Repeated at 10 yard intervals to 70 yards.
Results: Absolutely no difference in point of impact (POI) between field tips and broad heads at any distance up to and including 70 yards.
Discussion: By the time I shot at 70 yards I was a little shaky, saw sun spots when aiming and wanted to stop for the morning. Adding to those distractions was the appearance of the grounds keeper who wanted to mow the property and asked me to leave. I asked for and got 10 minutes to shoot at 70 yards. That allowed me to confirm both arrow tips as hitting within the same group, but the groups were probably 10 - 14 inches. I plan to repeat that distance. I have one more pin available to shoot at 80 yards, but ran out of parking lot room, so for now 70 yards is my maximum distance.
As far as I'm concerned, my questions have been answered:
1. The fixed point G5 Montec CS "flies like a field tip" and groups at the same POI as my field tip.
2. The 2" Blazer vanes provide adequate steering of the broad head at velocities up to and including 273 fps with no need to "tune" and no indication of wind planing.
3. The G5 Montec CS is symmetrical with respect to blade placement, rotates smoothly around its axis and is more rugged than any replaceable blade hunting point I've seen.
4. The CS version (carbon steel) can be re-sharpened with the G5 proprietary stone to a hair shaving edge.
Probably, before hunting season I'll set the bow at 60# and test to see if the arrows perform as well at 294 fps.
Harley
--------------------------
I've discovered that, when building an arrow, there are different ways to compute Front of Center (FOC) and different measurements to be used in those computations, none of them better than any other if you regard them as measures of relative performance among components. One of those I used showed no difference in FOC between combo field points and the fixed blade Montec CS, with an FOC of 14.3%. The main measurement influencing that result was assuming the total arrow length to be from the nock pocket to the end of the shaft behind the insert.
I've also computed a different formula which utilizes a total arrow length from the nock pocket to the actual tip of the point. With the Montec CS the resulting FOC was 10.9%; with the field tip the FOC was 12.4%. I think the reason the field tip has a higher FOC is because it has more weight concentrated in the very end of the tip than the raked back broad head.
Since Easton regards 7-15% FOC as acceptable I'm satisfied that I'm in the ballpark.
I doubt that the 1.4% difference in FOC between my broad head and field point will result in any significantly measureable difference on target AT ANY RANGE. You are not changing weight distribution around the longitudinal axis of the shaft by switching from a field point to a broad head IF (big IF) the broad head is both symmetrical with regard to its blades and centered with regard to the shaft. For instance, 100 grains is 100 grains, whether it's field point or broad head, and the FOC is not changed significantly when you replace the field point with the same weight broad head.
I recently read, and tend to believe, that there should be no need to "tune" broad heads; that they require no more than being absolutely aligned and symmetrical. Given that, they should hit POI where the field points hit. Anyway, I can't tune my broad heads because I've epoxied the inserts into my shafts.
I would add two observations, though:
1. Probably very few broadheads are that well centered.
2. There's always the chance that your broad head may require more steering than your present fletching provides.
I'm not arguing that most people won't have to tune their broad heads, but it's because their broad heads don't meet the specifications I've set up.
Of much more concern to me is whether or not the relatively small, slightly offset 2" Blazers will be able to steer the broad head at longer ranges to the target. I'm thinking that "tuning"; i.e., aligning the blades with the vanes is not the answer, although it can't hurt. If the Blazers won't steer the broad head, maybe I should try either longer and/or taller vanes and/or more helical. I don't want to do anything, of course, both because of the effort involved and the fact that any of the above modifications would slow the arrow.
I've always tuned my setup without a quiver and always remove the quiver once I'm in my stand.
It's not important to me that the fixed blades hit the same POI as my field points; worst case scenario is to tune the bow for them before hunting season.
For testing, I bought two 3-packs of 100gn G5 CS, one 3-pack of pre-season practice heads and the sharpening stone.
First, I tested sharpness against hair on my arm; they cut as well as any I've ever tried, what someone called "scary sharp"; so, I'm no longer worried about that. I've never tried the regular G5's, so don't know if they are as sharp as the CS, but I suspect they aren't.
The sharpening stone looks great, and the cordura case is perfect for it.
The pre-season practice blades are colored black and coated with a slippery substance for easier target removal. Look good.
Next, I weighed all the blades on my RCBS Chargemaster 1500 digital scale (claimed reliability + or - .1 gn). Each blade was weighed twice and I kept the different packs apart in order to test variances among "lots".
Pre-season blades:
102.4
102.8
102.8
The average was 102.7 gns. The spread among them was .4 gns.
Lot 1 100 gn G5 CS:
98.5
98.9
98.2
The average was 98.5 gns. The spread among them was .7 gns.
Lot 2:
98.9
97.9
98.5
The average among them was 98.4 gns. The spread was 1.0 gn.
In the real world, the overall extreme spread of 1 gn among the six points means nothing, but the lightest of them is 2.1 gns lighter than advertised; and the average weight is ~ 1.5 gns light.
The practice points are within .4 gns of each other, but still average 2.7 gns heavier than they should be.
Conclusion:
I expect the practice points to group together, but I'll still have to shoot the "real" points to confirm zero-in for hunting season.A grain and a half lighter hunting tip will move the F.O.C. back a bit, but not significantly.
The dull practice G5's penetrate the target 4-6 inches deeper than the field points of the same weight.
The field points and the practice G5's have the same point of impact.
Because my inserts are epoxied, I couldn't rotate them to "tune" the broadhead with the Blazer vanes. Although the blades ended up in various degrees relative to the vanes, I didn't see any effect at all.
The practice blades would quickly destroy either a target or my Glendale buck; they are too dull to cut as you pull them back out, so they would be either trapped or pull the stuffing out of the target. I've decided to retire them, and shoot the actual broad head at targets, then re-sharpen them.
I missed the entire target with one shot and the G5 broad head buried about half its length in a Sweet Gum tree. I had to use a hammer and chisel to retrieve it. The good news is it wasn't damaged, and would STILL shave hair on my arm. If I can ever dull them, I'll try the new sharpener. They are still sharp after maybe 15 shots each.
I shot until failing light at 20 yards with the hunting G5's; when I could call my shots; i.e., know that I did everything correctly, I got ~ 1" groups.
I'm shooting the 60# pound bow set at 50# because it pains me less; if anything, this reduced draw weight should result in a sloppier performance from the bow, but it doesn't seem so.
I'm in the middle of a learning curve with the G5 sharpening stone; spent some time sharpening my G5 broadheads. It's no trick to get them to the point of cleanly cutting paper, but I'm having trouble making them hair-shaving sharp. I think I just need to practice.
I've now scraped so much hair from my arm with the G5 broadheads that it looks as if it's been licked by a tiger. I'm finally more or less satisfied; what sharpening boils down to is an "art", not a "science". The directions use words like "moderate pressure" and "light pressure" and "3-12 repetitions". What's "light" mean, or "moderate"? I just had to keep on working at it until I got it. I think I can get the points sharper over time, but have every confidence they are sharp enough, right now.
All I have left to do before completely endorsing the G5 is to shoot it at extended ranges as a check on "steering".
Final testing:
At daybreak this morning the wind was calm and the forecast was rain later in the afternoon, so I loaded up and went to a nearby church parking lot to shoot. There is a berm there that fronts the volleyball court and makes a fairly good but sloping away backstop. Nobody was around so I decided I didn't need a permit
I set my 2x2 target so that I was facing south, but as luck would have it, being left handed, I was staring to the east at the rising sun. That was not only uncomfortable, but the resulting squint cost me some sharpness looking at the target at the longer ranges I eventually shot.
Setup:
Bow: Mathews Z7, 60# design weight, set at 50#. Q.A.D. drop-away rest. Anchor Sight (peep substitute). Vital Gear Star Pro slider bow sight. Single caliper release. D-loop.
Arrows: Redhead (BassPro) Carbon Maxx 2000, 7.3 gpi, 26 5/8ยจ length from bottom of nock pocket to behind insert. Q.A.D. nock. 100 gn point, either combo field tip or G5 Montec CS. Front of center (FOC) variously calculated between 10.9% and 14.3%.
Muzzle velocity: 273 fps at 50# draw weight; measured three feet in front of chrony
Methodology: Beginning at 20 yards, zeroed the target with field points, then shot broadheads into the resulting group without first removing the field tip arrows. Repeated at 10 yard intervals to 70 yards.
Results: Absolutely no difference in point of impact (POI) between field tips and broad heads at any distance up to and including 70 yards.
Discussion: By the time I shot at 70 yards I was a little shaky, saw sun spots when aiming and wanted to stop for the morning. Adding to those distractions was the appearance of the grounds keeper who wanted to mow the property and asked me to leave. I asked for and got 10 minutes to shoot at 70 yards. That allowed me to confirm both arrow tips as hitting within the same group, but the groups were probably 10 - 14 inches. I plan to repeat that distance. I have one more pin available to shoot at 80 yards, but ran out of parking lot room, so for now 70 yards is my maximum distance.
As far as I'm concerned, my questions have been answered:
1. The fixed point G5 Montec CS "flies like a field tip" and groups at the same POI as my field tip.
2. The 2" Blazer vanes provide adequate steering of the broad head at velocities up to and including 273 fps with no need to "tune" and no indication of wind planing.
3. The G5 Montec CS is symmetrical with respect to blade placement, rotates smoothly around its axis and is more rugged than any replaceable blade hunting point I've seen.
4. The CS version (carbon steel) can be re-sharpened with the G5 proprietary stone to a hair shaving edge.
Probably, before hunting season I'll set the bow at 60# and test to see if the arrows perform as well at 294 fps.
Harley