Bartlein Barrel - 7mm B#12 Heavy Palma

Discover the world of precision shooting with Bartlein Barrels' 7mm B#12 Heavy Palma barrel. Dive into the details of barrel contours, rifling styles, and fluting, and learn why these factors can make a significant difference in your shooting experience.

Does Barrel Contour Affect Performance?

Yes, barrel contour plays a crucial role in your rifle's performance. Heavier contours can offer advantages, especially when it comes to maintaining accuracy during prolonged shooting sessions. Residual stress in barrels, often found in button-rifled barrels, can cause groups to wander when the barrel heats up. Heavier contours help resist this wandering effect.

At Bartlein Barrels, we exclusively use single-point cut rifling, which eliminates stress in the barrel blank. This makes the contour less critical compared to button-rifled barrels.

Does Contour Impact Shooting Quality?

Indeed, contour affects shooting quality. Heavier barrels typically result in improved shooting performance. The added weight helps shooters manage recoil and reduces fatigue, allowing for extended shooting sessions with greater accuracy.

However, it's worth noting that we've witnessed lighter weight contours perform exceptionally well, sometimes even outperforming heavier counterparts. So while contour matters, it may not be as critical as some believe.

Should Suppressors Be Used with Any Contour?

No, suppressors should not be indiscriminately used with any barrel contour. When mounting a suppressor on a heavier barrel, it tends to perform better. This is because the added weight at the muzzle end affects the barrel's harmonic vibrations. For suppressor use, we recommend a barrel with at least a medium palma contour for optimal results.

Why is Single-Point Cut Rifling Superior?

Single-point cut rifling, as exclusively done by Bartlein Barrels, offers significant advantages over button rifling. In button-rifled barrels, the stress applied to the blank increases as the contour size decreases. This can lead to bore size changes and openings that cannot be easily corrected. Single-point cut rifling does not suffer from this issue, ensuring consistent bore dimensions.

Additionally, threading the muzzle for a muzzle brake or suppressor attachment can be problematic with button-rifled barrels, as it may cause the bore to open up. This can negatively impact accuracy, especially at the crown edge.

Why is Fluting Important?

Fluting serves multiple purposes:

• Weight Reduction: Fluting removes material from the barrel, reducing its weight without altering the contour.
• Enhanced Barrel Cooling: The increased surface area created by fluting enhances heat dissipation during extended shooting sessions.
• Aesthetic Appeal: Many customers appreciate the unique appearance that fluting adds to their barrel.

Questions About Fluting:

Minimum Depth for Fluting: Fluting can be done too deep, potentially causing harmonic and vibration issues that affect accuracy. If you cannot add fluting during your barrel selection, it may indicate that the contour is too shallow.

Does Fluting Make the Barrel Stiffer? Fluting typically reduces the stiffness of the barrel. The level of stiffness can vary depending on how it's measured. In general, a fluted barrel is not as stiff as an identical non-fluted one.

The Importance of Rifling Styles

Choosing the right rifling style is essential for precision shooting. At Bartlein Barrels, we offer three rifling types: 4-groove, 5R, and Conventional-5. The number of grooves does not significantly affect accuracy or barrel life.

Additional Benefits of 5R Rifling:

The 5R rifling style offers unique advantages, such as reduced bullet deformation and improved flight characteristics. Its gentler angle on the sides of the lands and odd number of lands contribute to minimizing bullet failure.

We've learned that 5R rifling can even enhance bullet flight, as confirmed by ammunition and bullet manufacturers in late 2019.

A Few Exceptions: Short jacket 6mm bullets, typically in the 65-68gr range, used by short-range bench shooters may not perform optimally with 5R rifling. The combination of short bearing surface and 5R rifling may result in less-than-ideal accuracy.

When choosing the perfect barrel for your shooting needs, consider these factors carefully to achieve the precision and performance you desire.