My gun has an 18" barrel with 1:10 twist. I am not able to use a chronograph yet, but I was wondering what velocity I would be looking at using Federal 168 gr BTHP. On top of that, what type of differences would I be looking at with bullet drop between the 300-1000 yard marks? Has anybody created data based on an 18" barrel with the ammunition I am using? I just want to see what changes from the standard ballistic data.
Range Report Ballistic Changes with 18" barrel
- Thread starter Trubester88
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Re: Ballistic Changes with 18" barrel
From a 18" gas gun you should see around 2525-2550 with the 168smk
The 168 is great for 600 and in but it starts to fall on it's face after 800 in most cases. Use the 175 SMK/Berger or the 155 Scenar/Berger.
The boattails on the 168 SMK has a steep angle and transition poorly once it goes subsonic that's why it's not the bullet of choice for anything past 800 yards. 500 yards and in though, I have found they are a hair more accurate then the 175 SMKs
From a 18" gas gun you should see around 2525-2550 with the 168smk
The 168 is great for 600 and in but it starts to fall on it's face after 800 in most cases. Use the 175 SMK/Berger or the 155 Scenar/Berger.
The boattails on the 168 SMK has a steep angle and transition poorly once it goes subsonic that's why it's not the bullet of choice for anything past 800 yards. 500 yards and in though, I have found they are a hair more accurate then the 175 SMKs
Re: Ballistic Changes with 18" barrel
DTA SRS Covert with an 18" Bartlein 10-twist barrel:
FGMM 168 gr = 2591 fps (mean of of 2 x 10-shot string average MVs; String 1 = 2582 fps, String 2 = 2600 fps)
As Pusher stated, the 168s in your setup are not going to be ideal past ~800 yd. At 2591 fps, they will be going trans-/sub-sonic before 900 yd, which the 168 gr SMK doesn't handle too well. The 2591 fps MV was from a bolt gun, so you're probably looking at slightly less than 2591 fps. The Hornady 168 gr A-Max will do a little better, but still not where you would like to be at 1000 yd. I've used 155 gr Scenars (CorBon factory load) from this setup at better than 2800 fps, and they shoot very well from the 18" 10-twist barrel. If you can push 155 gr Scenars close to 2800 fps, you'll be doing better out to 1000 yd than wih either of the 168s mentioned above.
DTA SRS Covert with an 18" Bartlein 10-twist barrel:
FGMM 168 gr = 2591 fps (mean of of 2 x 10-shot string average MVs; String 1 = 2582 fps, String 2 = 2600 fps)
As Pusher stated, the 168s in your setup are not going to be ideal past ~800 yd. At 2591 fps, they will be going trans-/sub-sonic before 900 yd, which the 168 gr SMK doesn't handle too well. The 2591 fps MV was from a bolt gun, so you're probably looking at slightly less than 2591 fps. The Hornady 168 gr A-Max will do a little better, but still not where you would like to be at 1000 yd. I've used 155 gr Scenars (CorBon factory load) from this setup at better than 2800 fps, and they shoot very well from the 18" 10-twist barrel. If you can push 155 gr Scenars close to 2800 fps, you'll be doing better out to 1000 yd than wih either of the 168s mentioned above.
Re: Ballistic Changes with 18" barrel
Thank you for the info. I will stick with the 168 gr and shoot to 800 yards. I don't expect to do anything past that, but what type of drop difference will I be expecting out to 800 yards? Is it extreme or enough to spot easily on the range. I just hope that I can see it hit paper and then make simple adjustments rather than guess. I could work in 25 yard increments if I must. I just can't wait to get back home and start working on my own bullet data book. Less than a month in this hell hole country.
Thank you for the info. I will stick with the 168 gr and shoot to 800 yards. I don't expect to do anything past that, but what type of drop difference will I be expecting out to 800 yards? Is it extreme or enough to spot easily on the range. I just hope that I can see it hit paper and then make simple adjustments rather than guess. I could work in 25 yard increments if I must. I just can't wait to get back home and start working on my own bullet data book. Less than a month in this hell hole country.
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