Bullet weight deviation.

Willy · July 5, 2001, 10:13 PM

I have to admit up front that I was playing around with my new digital scale and was looking for something to weigh.

I took a box of Speer 150 grain bullets and started weighing each. I got a range from 150.3 grains to 147.5. Most of the bullets were 147.7. About 30% of them.

What do you think is the normal deviation in weight for bullets?

All things considered, do you think that this is a large deviation and would have a noticable effect on group size?

**Mal H** · July 5, 2001, 11:33 PM

Willy - You're not alone. I think we've all done that when we got one of those new fangled digital scales. In fact some of us did it with old beam scales. And I dare say we were all surprised to see how much variation there is in bullet weights in a box of average bullets ("match" bullets should have less variation). It seems the heavier the bullet the more difference there is in total grains. But I also think the percentage difference is roughly the same. That is, a box of 45 gr. .224 bullets will all be a lot closer to the same weight. Whereas a box of slugs will make your 3 gr. difference look small by comparison.

Your box of bullets has a percentage variation of roughly 2%. So will that 2% difference make a noticable difference at the target end of the trip? Probably not. My reason is that you, a human, will be doing the shooting and the variables you yourself introduce will far outweigh the difference in bullet weight. On the other hand, if you were to load some rounds with precisely weighed loads of powder in cases that are precisely the same and fired them in an anchored receiver, then you should be able to measure the difference the bullets alone will make.

saands · July 6, 2001, 11:10 PM

I think it will make less difference than you might suspect. I've plotted some data of velocity versus powder charge and there is an amazing thing that shows (for Alliant powders with pistol rounds at least) that the charge is what dictates the velocity. Now with lighter bullets, you can up the charge and safely get higher velocities, but the same charge looks like it will produce the same velocity in a pretty wide range of bullet weights. Based on this limited study, I'd concentrate on getting uniform charges!

FWIW,
Saands

**Mike Irwin** · July 7, 2001, 12:49 AM

That works out to about what, less than 2% deviation from the stated weight?

That's pretty much within what I've always seen out of production line bullets.

I don't think you're going to be able to notice a difference in performance at all.

blades67 · July 8, 2001, 01:40 AM

I've seen velocity variations greater than 2%, so I'm not sure it would make a great difference.

MIKE14 · July 9, 2001, 07:07 PM

The most consistant bullet I've used yet has been the Nosler J4 155 gr HPBT the entire box varied from 154.8 to 155.2 grains. each different weight bullet was loaded together and shot as a group. all these loads grouped well from my M1A and all of them exibited single digit standard deviations. all of these were over the same charge. I believe it is worth the extra effort to do this. However I would not go to this extreme for loads for my FAL. I think that if you have a rifle that will shoot 1MOA weighing and grouping the bullets could shave .25 inch off your group. JMO

DAVID NANCARROW · July 11, 2001, 12:58 PM

Mike 14. Guess I'll have to try some of those J-4 jacketed 155'! Just weighed a box of Sierra Palma Match 155 grain, and the variation was .9 grain. Have segregated by weight, as well as with the cases as I always do, and it does seem to get me at 1/4 inch or less at 100 yards. Have heard all the stories about how I'm wasting my time, but it is a confidence builder for me.

MIKE14 · July 12, 2001, 06:39 AM

David an additional bonus with the J4's is the fact they cost two bucks less per 100 than the Sierra 155 Palma's Also the Nosler 150gr balistic tips are as consistant as the J4's but cost more they work well in my M1A hopefuly in the next week or so I'll be able to try them at 300 yds. The range where I normaly shoot only has 100 yards if I see how well they do at 300 yds I might try a 168 gr J4 I used to think Sierra was the cats ass but Nosler seems to be much better. All rifles like different loads my Springfield likes the Noslers.

DAVID NANCARROW · July 12, 2001, 07:34 AM

Thanks for the info, Mike 14. I have used 150 and 165 grain Ballistic Tips for deer hunting for years, and they have yet to fail me for accuracy or expansion. Was warned not to try shoulder shots because the bullet would blow up/fall to the ground/bambi would just eat the thing, but I have not found this to be true. The accuracy is good enough for head shots out to any kind of distance I have any business with, and pretty much, if I can make a body shot with a ballistic tip, I can make a head shot as well. Off to the store I go!

July 5, 2001, 10:13 PM	#1
Willy Senior Member Join Date: March 19, 1999 Posts: 147	Bullet weight deviation. I have to admit up front that I was playing around with my new digital scale and was looking for something to weigh. I took a box of Speer 150 grain bullets and started weighing each. I got a range from 150.3 grains to 147.5. Most of the bullets were 147.7. About 30% of them. What do you think is the normal deviation in weight for bullets? All things considered, do you think that this is a large deviation and would have a noticable effect on group size?

July 7, 2001, 12:49 AM	#4
Mike Irwin Staff Join Date: April 13, 2000 Location: Northern Virginia Posts: 41,390	That works out to about what, less than 2% deviation from the stated weight? That's pretty much within what I've always seen out of production line bullets. I don't think you're going to be able to notice a difference in performance at all. __________________ "The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza Baby Jesus cries when the fat redneck doesn't have military-grade firepower.

July 8, 2001, 01:40 AM	#5
blades67 Senior Member Join Date: April 22, 1999 Location: Chandler, Arizona, USA Posts: 6,014	I've seen velocity variations greater than 2%, so I'm not sure it would make a great difference. __________________ Guns cause crime like spoons cause Rosie O'Donnell to be fat! I hunt, therefore I am.

July 9, 2001, 07:07 PM	#6
MIKE14 Senior Member Join Date: November 26, 2000 Posts: 147	The most consistant bullet I've used yet has been the Nosler J4 155 gr HPBT the entire box varied from 154.8 to 155.2 grains. each different weight bullet was loaded together and shot as a group. all these loads grouped well from my M1A and all of them exibited single digit standard deviations. all of these were over the same charge. I believe it is worth the extra effort to do this. However I would not go to this extreme for loads for my FAL. I think that if you have a rifle that will shoot 1MOA weighing and grouping the bullets could shave .25 inch off your group. JMO __________________ M-14 OUT

July 12, 2001, 06:39 AM	#8
MIKE14 Senior Member Join Date: November 26, 2000 Posts: 147	David an additional bonus with the J4's is the fact they cost two bucks less per 100 than the Sierra 155 Palma's Also the Nosler 150gr balistic tips are as consistant as the J4's but cost more they work well in my M1A hopefuly in the next week or so I'll be able to try them at 300 yds. The range where I normaly shoot only has 100 yards if I see how well they do at 300 yds I might try a 168 gr J4 I used to think Sierra was the cats ass but Nosler seems to be much better. All rifles like different loads my Springfield likes the Noslers. __________________ M-14 OUT

July 5, 2001, 11:33 PM	#2
Mal H Staff Join Date: March 20, 1999 Location: Somewhere in the woods of Northern Virginia Posts: 16,955	Willy - You're not alone. I think we've all done that when we got one of those new fangled digital scales. In fact some of us did it with old beam scales. And I dare say we were all surprised to see how much variation there is in bullet weights in a box of average bullets ("match" bullets should have less variation). It seems the heavier the bullet the more difference there is in total grains. But I also think the percentage difference is roughly the same. That is, a box of 45 gr. .224 bullets will all be a lot closer to the same weight. Whereas a box of slugs will make your 3 gr. difference look small by comparison. Your box of bullets has a percentage variation of roughly 2%. So will that 2% difference make a noticable difference at the target end of the trip? Probably not. My reason is that you, a human, will be doing the shooting and the variables you yourself introduce will far outweigh the difference in bullet weight. On the other hand, if you were to load some rounds with precisely weighed loads of powder in cases that are precisely the same and fired them in an anchored receiver, then you should be able to measure the difference the bullets alone will make.

July 6, 2001, 11:10 PM	#3
saands Senior Member Join Date: November 14, 1999 Posts: 1,573	I think it will make less difference than you might suspect. I've plotted some data of velocity versus powder charge and there is an amazing thing that shows (for Alliant powders with pistol rounds at least) that the charge is what dictates the velocity. Now with lighter bullets, you can up the charge and safely get higher velocities, but the same charge looks like it will produce the same velocity in a pretty wide range of bullet weights. Based on this limited study, I'd concentrate on getting uniform charges! FWIW, Saands

July 11, 2001, 12:58 PM	#7
DAVID NANCARROW Senior Member Join Date: November 5, 2000 Location: Wyoming Posts: 1,761	Mike 14. Guess I'll have to try some of those J-4 jacketed 155'! Just weighed a box of Sierra Palma Match 155 grain, and the variation was .9 grain. Have segregated by weight, as well as with the cases as I always do, and it does seem to get me at 1/4 inch or less at 100 yards. Have heard all the stories about how I'm wasting my time, but it is a confidence builder for me.

July 12, 2001, 07:34 AM	#9
DAVID NANCARROW Senior Member Join Date: November 5, 2000 Location: Wyoming Posts: 1,761	Thanks for the info, Mike 14. I have used 150 and 165 grain Ballistic Tips for deer hunting for years, and they have yet to fail me for accuracy or expansion. Was warned not to try shoulder shots because the bullet would blow up/fall to the ground/bambi would just eat the thing, but I have not found this to be true. The accuracy is good enough for head shots out to any kind of distance I have any business with, and pretty much, if I can make a body shot with a ballistic tip, I can make a head shot as well. Off to the store I go!