Sierra MK 175 or Berger HPBT?

[chemist308]

While I was looking for Sierra Match King 175 grain bullets and struggling with Berger's VLD, I picked up a box of Berger 175 Grain Hollow Point Boat target bullets. Is there much difference in trajectory between the Sierra MK 175 and Berger HPBT 175 out to 400 - 600 yards? I was thinking to practice with these, but if there is a huge difference I suppose I can always trade with some of the guys that swear by them. They're more expensive anyway. What are your thoughts?

 

[Reloadron]

You can try using the Bison Ballistic Calculator. This ballistic calculator covers both the bullets you are using. Additionally, Berger Bullets also has their own ballistic calculator which can be found here. Did you ever find good loading data for the Berger 175 gn .308 you have?

Anyway, the calculators should help with bullet characteristics at the ranges you mention.

Ron

 

[Sunray]

You should practice with the same ammo you shoot in matches.

 

[jwrowland77]

You should practice with the same ammo you shoot in matches.

+1 right here.

 

[Reloadron]

You should practice with the same ammo you shoot in matches.

For those not up on chemist308's situation. He is away from home. He wanted to purchase some Sierra Match King 175gr bullets. Unfortunately he was unable to find any but was able to find some Berger VLD 175 grain bullets. Unfortunately the only published data for the Berger bullets is in the Berger reloading manual. He was looking for data in a few other threads. In one thread he was looking for a COL to work up seating depths.

I don't think he shoots in matches but is trying to work up some load data. Unfortunately what he is trying to do is spread over a few threads. What he really needs is someone with a Berger bullet loading manual. That or 175gn Sierra MK bullets.

Ron

 

[chemist308]

Thanks Ron. Actually I flat gave up the VLDs. Too much of PIA trying to get it just the right distance from the lands. What I did do was get about 200 Sierra Match King (SMK) 175 gr bullets from Midway, and before I did that I talked to a guy knowledgeable about Bergers with Sinclair. That guy suggested I try the Berger Hollow Point Boat Tail (HPBT) target bullets, so I've got a box of 100 of those now, and I'm running low on SMKs.

The nice thing about the Berger HPBT is that like the SMK they're actually designed to be loaded to the 308 COAL of 2.800." I was really just wondering if anyone that has shot the Berger HPBT had noted much of a difference between SMK and the Berger HPBT.

As for the load, I picked up a Lee balance--if you could call it that--and started weighing H-4895. I went off of the data on Hodgdon went for the higher end of their weight range, coming in 0.3 gn below their max load. The Hodgdon site gives data for the 175 gn Sierra Hollow Point Boat tail, which is what their Match King is.

I also picked up a caliper and started checking my COALs. So the current load is 175 SMK with 42.4gn of H-4895 pushing it. After their first neck sizing, cases were trimmed with a Lee trimmer, and all loads are within 0.005" of the 2.800" COAL standard. My current ballistics are tracking with the drop table the range instructor who qualified me for 600 yards gave me, so I figure it's right where it should be.

Interestingly, the length of the Berger HPBT measures 1.321" while the SMK measures 1.244." Both have curved, sloped shape leading to the hollow point. But the length difference makes me wonder if I'm in for a pressure difference and need to back off the powder...

The Berger VLD measures close to the HPBT but is shaped slightly different. But again I gave up on those VLD ones.

 

[chemist308]

Okay, nevermind. I just learned that these Berger HPBT bullets are meant to be "tuned" as well. What a PITA :banghead:

Learned my lesson with Berger. Hopefully I find a local who likes them to trade with.

 

[Reloadron]

Actually the Berger bullets are very good bullets but yes, they require patience and work to get the most out of them. That also can be said about other bullets also depending on how OCD we want to get with our hand loading. The following is from our friends at Berger Bullets as to tuning:

VLD bullets are extremely efficient in the wind and have very high BCs, but they are sensitive to seating depth and require time and effort to “tune” the load for each rifle. Some people thought the VLD was the ultimate design, but Berger’s Chief Ballistician Bryan Litz saw room for improvement and went to work designing a bullet that would give shooters the high performance of VLD bullets but would be less sensitive to seating depth. The result was the Berger Hybrid bullet.

As to bullet seating depth when we get away from the standard seating depths called out in our manuals:

The following instructions were taken from the Nosler website FAQ section.

How to measure your rifle’s seating depth.

Step 1: Insert the bullet into the neck of the fired case. It should fall freely into the case with no resistance.

Step 2: Remove the bullet from the fired case and press the case neck lightly against a flat surface to create a small indentation in the case neck so that it will grip the bullet.

Step 3: Insert the bullet, base first into the case so that the case just grips the bullet by itself. Just get the bullet started into the case, don’t seat it too deeply.

Step 4: Completely color the bullet with a felt marker.

Step 5: Gently insert the case and bullet into the chamber of the firearm and close the action. Do not pull the trigger.

Step 6: Carefully open the action and gently remove the case.

Step 7: Retrieve the bullet. It will either be stuck in the lands of the barrel or still in the case. If the bullet is stick in the lands, it can be removed with a cleaning rod. If the bullet is still in the case, gently remove it with your fingers taking care not to mar the ink and proceed to step 8.

Step 8: During Step 5, the lands will have contacted the bullet and pushed it back into the case neck to scrape the ink off of the bearing surface of the bullet. Simply push the bullet into the case until the edge of the case neck is just to where the ink has been scraped off.

Step 9: Carefully measure the overall length of the dummy cartridge. This overall length is called your “rifle seating” depth. It is where the bullet contacts the lands of the barrel. This length is different for every type of bullet depending on ogive, meplat, etc. This process should be repeated three to four times to obtain a consistent average.

Step 10: Set your seating die to seat at a depth between .015” and .03” less than your rifle seating depth.

When loading E-Tip® bullets, seating them .050” - .100” away from the lands typically produces the best accuracy.
Lightweight bullets may need to be seated further from the rifling. A depth of one bullet diameter inside the case neck gives good neck tension for ignition.
The overall length must be short enough to function through the magazine.

So when we don't have any of the marketed gauges like the RCBS Precision Mic the above method will be a good start. Don't know if you have that so I posted it.

For 308 Winchester I like H-4895, IMR-4895, IMR-4064 and in my bolt gun I have had very good success using Accurate Arms 2496 with Sierra 168 gr BTHP Match bullets. Every rifle is different.

Glad you have a better scale now and more bullets to experiment with.

Ron